Alonso MP. de Abajo FJ. Martinez JJ. Montero D. Martin-Serrano G. Madurga M.: Evolution of antidepressive drug consumption in Spain. The impact of selective serotonin re-uptake inhibitors. Medicina Clinica. 1997;108(5):161-6.
Avorn J. Putting adverse drug events into perspective [editorial]. JAMA 1997;277(4):341-2.
Choo PW. Galil K. Donahue JG. Walker AM. Spiegelman D. Platt R. Risk factors for postherpetic neuralgia. Archives of Internal Medicine. 1997;157(11):1217-24.
Gurwitz JH. Kalish SC. Bohn RL. Glynn RJ. Monane M. Mogun H. Avorn J. Thiazide diuretics and the initiation of anti-gout therapy. Journal of Clinical Epidemiology. 1997;50(8):953-9.
Gurwitz JH. Monette J. Rochon PA. Eckler MA. Avorn J. Atrial fibrillation and stroke prevention with warfarin in the long-term care setting. Archives of Internal Medicine. 1997;157(9):978-84.
Harari D. Gurwitz JH. Avorn J. Bohn R. Minaker KL. How do older persons define constipation? Implications for therapeutic management. Journal of General Internal Medicine. 1997;12(1):63-6.
Huttin C. Avorn J. Drug expenditures for hypertension: an empirical test of an economic model in a French population. Cahiers de Sociologie et de Demographie Medicales. 1997;37(1):33-52.
Kalish SC. Bohn RL. Avorn J. Policy analysis of the conversion of histamine2 antagonists to over-the-counter use. Medical Care. 1997;35(1):32-48.
Lanes SF. Birmann B. Raiford D. Walker AM. International trends in sales of inhaled fenoterol, all inhaled beta-agonists, and asthma mortality, 1970-1992. Journal of Clinical Epidemiology. 1997;50(3):321-8.
Lanes SF. Lanza LL. Radensky PW. Yood RA. Meenan RF. Walker AM. Dreyer NA. Resource utilization and cost of care for rheumatoid arthritis and osteoarthritis in a managed care setting: the importance of drug and surgery costs. Arthritis & Rheumatism. 1997;40(8):1475-81.
Liese JG. Meschievitz CK. Harzer E. Froeschle J. Hosbach P. Hoppe JE. Porter F. Stojanov S. Niinivaara K. Walker AM. Belohradsky BH. Adisdutschmann B. Busching U. Burk M. Bartels R. Berger S. Berger W. Bergner A. Binder K. Bittmann B. Borgmeyer A. Braun H. Breiner W. Daubuisson CC. Domay J. Enzel U. et al.: Efficay of a Two-Component Acellular Pertussis Vaccine in Infants. Pediatric Infectious Disease Journal. 1997;16(11):1038-1044.
Monane M. Bohn RL. Gurwitz JH. Glynn RJ. Levin R. Avorn J. The effects of initial drug choice and comorbidity on antihypertensive therapy compliance: results from a population-based study in the elderly. American Journal of Hypertension. 1997;10(7):697-704.
Monane M. Gurwitz JH. Bohn RL. Glynn RJ. Levin R. Monette J. Avorn J. The impact of thiazide diuretics on the initiation of lipid-reducing agents in older people: a population-based analysis. Journal of the American Geriatrics Society. 1997;45(1):71-5.
Monette J. Gurwitz JH. Rochon PA. Avorn J. Physician attitudes concerning warfarin for stroke prevention in atrial fibrillation: results of a survey of long-term care practitioners. Journal of the American Geriatrics Society. 1997;45(9):1060-5.
Monette J. Mogun H. Bohn RL. Avorn J. Concurrent use of antiulcerative agents. Journal of Clinical Gastroenterology 1997;24(4):207-13.
Rothman KJ. Cann CI. Walker AM. Epidemiology and the internet [editorial]. Epidemiology. 1997;8(2):123-5.
Schneeweiss S, Stürmer T, MaclureM: Case-Crossover and Case-Time-Control Designs as Alternatives in Pharmacoepidemiologic Research. Pharmacoepidemiology and Drug Safety 1997;6 S3:S51-S59.
Walker AM. Quantitative studies of the risk of serious hepatic injury in persons using nonsteroidal antiinflammatory drugs. Arthritis & Rheumatism. 1997;40(2):201-8.
Walker AM. Funch DP. Bianchi L. Blot WJ. Shop order fracture rate as a risk factor for strut fracture in Bjork-Shiley CC60 degrees heart valves. Journal of Heart Valve Disease. 1997;6(3):264-7; discussion p268.
Walker AM. Szneke P. Bianchi LA. Field LG. Sutherland LR. Dreyer NA. 5-Aminosalicylates, sulfa-salazine, steroid use, and complications in patients with ulcerative colitis. American Journal of Gastroenterology. 1997;92(5):816-20.
Zatonski WA. Lowenfels AB. Boyle P. Maisonneuve P.
Bueno de Mesquita HB. Ghadirian P. Jain M. Przewozniak
K. Baghurst P. Moerman CJ. Simard A. Howe GR.
McMichael AJ. Hsieh CC. Walker AM. Epidemiologic
aspects of gallbladder cancer: a case-control study of the SEARCH Program
of the International Agency for Research on Cancer. Journal of the
National Cancer Institute. 1997;89(15):1132-8.
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Abstract:
OBJECTIVE: To describe the frequency and costs of medical services
for patients with osteoarthritis (OA) or rheumatoid arthritis (RA) in a
managed care setting.
METHODS: Individual utilization records of medical and pharmacy services
for OA and RA patients were obtained from a group-model health maintenance
organization (HMO). Estimates were made for costs of drugs and medical
services for arthritis from July 1, 1993 to June 30, 1994 using Medicare
reimbursement schedules and average wholesale drug prices. Calculated rates
for each population were expressed as counts of events or as dollars per
person-year.
RESULTS: The average individual cost rate of arthritis-related care
for 365 RA patients was $2,162 per year, and the total cost of RA care
to the HMO was $703,053. Prescription medications accounted for 62% ($436,440)
of the total cost of RA care, while ambulatory care accounted for 21% ($150,938),
and hospital visits accounted for 16% ($115,674). With regard to 10,101
OA patients, the average individual cost rate was $543 per year, and total
cost to the HMO was $4,728,425. Hospital care accounted for 46% ($2,170,890)
of the total cost of OA care, medications accounted for 32% ($1,509,637),
and ambulatory care accounted for 22% ($1,047,898).
CONCLUSION: RA care, in the setting of this study, was characterized
by intensive treatment, especially frequent use of medications that were
delivered to most patients. Although the cost of RA care per patient was
high, cost to the managed care provider was relatively low, owing to the
rarity of RA. OA care tended to be infrequent, and the largest component
of cost was hospital care for a small proportion of patients (5%). Owing
to the greater prevalence of OA, care of OA was nearly 7 times more costly
to the managed care provider than was care of RA.
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Epidemiologic aspects of gallbladder cancer: a case-control study of the SEARCH Program of the International Agency for Research on Cancer. Journal of the National Cancer Institute. 1997;89(15):1132-8.
Abstract
BACKGROUND: There are few previous epidemiologic studies of gallbladder
cancer, a rare but nearly always lethal gastrointestinal cancer with a
demonstrated greater frequency in adult women and older subjects of both
sexes, and also in the members of populations throughout central and eastern
Europe and certain racial groups such as native American Indians. Unfortunately,
the prospects for the prevention of this form of cancer are poor.
PURPOSE: Our purpose in conducting this study was to investigate possible
new risk factors for gallbladder cancer and to strengthen our understanding
of established causal agents that may be involved in this disease.
METHODS: A large, collaborative, multicenter, case-control study of
cancer of the gallbladder was conducted in five centers located in Australia
(Adelaide), Canada (Montreal and Toronto), The Netherlands (Utrecht), and
Poland (Opole) from January 1983 through July 1988. Case subjects with
gallbladder cancer were accrued by the centers from hospital pathology
records and from reports to regional cancer registries. Cancer diagnosis
was confirmed by either biopsy, cholecystectomy, or at the time of autopsy.
Control subjects were randomly assigned at each center from the population.
The pooled analysis included 196 case subjects and 1515 control subjects
(who did not report previous cholecystectomy). Ninety-eight percent of
the subjects were white. Personal interviews of case subjects, control
subjects, and surrogates (spouse or next of kin) were conducted by trained
personnel.
RESULTS: After adjusting for potential confounding factors (age, sex,
center, type of interview, years of schooling, alcohol intake, and lifetime
cigarette smoking), a history of gallbladder symptoms requiring medical
attention (e.g., reduced bile secretion from the gallbladder into the small
intestine due to obstructions of the common bile or cystic ducts) was the
major risk factor associated with this form of cancer (odds ratio [OR]
= 4.4; 95% confidence interval [CI] = 2.6-7.5). This association was present
even in subjects who had their first gallbladder examination because of
symptoms present more than 20 years earlier (OR = 6.2; 95% CI = 2.8-13.4).
Other variables associated with gallbladder cancer risk included an elevated
body mass index, high total energy intake, high carbohydrate intake (after
adjustment for total energy intake), and chronic diarrhea. All of these
risk factors have been previously associated with gallstone disease.
CONCLUSIONS: These findings are consistent with a major role of gallstones,
or risk factors for gallstones, in the cause of gallbladder cancer. Additional
information on whether or not screening high-risk subjects for gallstones
or gallbladder cancer is needed.
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Abstract
OBJECTIVE: To quantify the risk of symptomatic hepatic injury associated
with nonsteroidal antiinflammatory drugs (NSAIDs). METHODS: Five population-based
studies were summarized to evaluate information on more than 1,000,000
patients using NSAIDs. RESULTS: The risk of clinically apparent liver injury
was approximately 1 case per 10,000 patient-years of NSAID use. Only sulindac,
associated with a 5-10-fold higher incidence of hepatic injury, differed
significantly from other NSAIDs. Patients using diclofenac showed no higher
incidence of serious liver disease than did patients using other NSAIDs.
CONCLUSION: Symptomatic hepatic effects attributable to most NSAIDs
are extremely rare and usually mild. [References: 11]
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Abstract
BACKGROUND: The risk factors for postherpetic neuralgia (PHN), the
most common complication of herpes zoster, have not been well established.
OBJECTIVE: To elucidate the risk factors for PHN. METHODS: Automated
medical, claims, and pharmacy records of a health maintenance organization
were used to identify cases of PHN and obtain data on risk factors. A case-base
design was used to assess the impact of various patient, disease, and treatment
factors on the prevalence of PHN 1 and 2 months after developing zoster.
RESULTS: There were 821 cases of herpes zoster that met all eligibility
criteria. The prevalence of PHN more than 30 days after onset of zoster
was 8.0% (95% confidence interval [CI], 6.3%-10.1%) and 4.5% (95% CI, 3.2%-6.2%)
after 60 days. Compared with patients younger than 50 years, individuals
aged 50 years or older had a 14.7-fold higher prevalence (95% CI, 6.8-32.0)
30 days and a 27.4-fold higher prevalence (95% CI, 8.8-85.4) 60 days after
developing zoster. Prodromal sensory symptoms and certain conditions associated
with compromised immunity were also associated with PHN. Systemic corticosteroids
before zoster and treatment of zoster with acyclovir or corticosteroids
did not significantly affect the prevalence of PHN.
CONCLUSIONS: Increased age and prodromal symptoms are associated with
higher prevalence of PHN 1 and 2 months after onset of zoster. Overall,
systemic acyclovir appears not to confer any protection against PHN, although
benefit among elderly patients cannot be excluded.
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Abstract
To evaluate the hypothesis that fenoterol or all inhaled beta-agonists
caused an epidemic of asthma mortality in New Zealand from the late 1970s
to the mid-1980s, we examined trends from 1970 to 1992 in per capita sales
of inhaled fenoterol, inhaled beta-agonists, and asthma mortality in New
Zealand and nine other countries that marketed fenoterol. During the last
two decades, there has been a large and widespread increase in sales of
inhaled beta-agonists, including fenoterol. Asthma mortality in most countries,
however, has been relatively stable. Only New Zealand experienced an epidemic
of asthma mortality. In addition, sales rates of fenoterol similar in magnitude
to those in New Zealand near the peak of the epidemic also occurred in
Belgium, Austria, and Germany, while asthma mortality in these countries
remained low. Also, sales rates of all beta-agonists in Australia were
similar to those in New Zealand, but no epidemic of asthma mortality occurred
in Australia. Therefore, the difference between asthma mortality rates
in New Zealand and other countries is not explained by differences in per
capita sales of fenoterol or all beta-agonists. Within New Zealand, the
beginning and end of the epidemic correlated with a rise and fall in sales
of all beta-agonists, including fenoterol. From 1980 to 1989, however,
sales of fenoterol and all beta-agonists doubled in New Zealand while asthma
mortality declined by 40%. International data on medication sales and asthma
mortality, therefore, do not point to a relation between asthma mortality
and beta-agonists in general nor fenoterol in particular.
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Abstract
BACKGROUND AND AIMS OF THE STUDY: Previous studies have implicated
a number of characteristics that predict strut fracture in Bjork-Shiley
convexo-concave heart valves, including valve size and position, opening
angle, and weld date. This study examines whether the specific batch (shop
order) with which a valve is associated during manufacture is related to
the risk of fracture.
MATERIAL AND METHODS: Our case-control study of CC60 degrees valves
obtained detailed information on the manufacturing characteristics of 147
case and 1094 control valves used. Shop order fracture rate for each valve
(percentage of other valves in the same shop order with a fracture) was
obtained from the research database maintained by the valve manufacturer.
RESULTS: Shop order was associated with fracture risk. Valves originating
from shop orders with the highest two categories of fracture rate were
at approximately twice the risk of fracture as other valves, after accounting
for the effect of known risk factors.
CONCLUSIONS: Shop order information may provide additional data for
assessing the likelihood of valve fracture in individuals being considered
for prophylactic explant of heart valves.
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Abstract
While physiologic and epidemiologic evidence link diuretic therapy
with hyperuricemia, no previous study has quantified the risk for initiation
of treatment specific for hyperuricemia or gout among elderly patients
taking thiazide diuretics. We performed a retrospective cohort study of
9249 enrollees aged 65 or older in the New Jersey Medicaid program who
were newly started on an antihypertensive medication from November 1981
through February 1989 and who had no prior use of anti-gout therapy (allopurinol,
colchicine, or a uricosutic) during the preceding one-year period. We used
Cox proportional hazards analysis to determine the risk for the initiation
of anti-gout therapy in patients using various antihypertensive treatment
regimens relative to no antihypertensive exposure. Patient follow-up extended
for up to two years. Antihypertensive exposure was characterized over the
entire period of follow-up according to the following categories: thiazide
diuretic therapy alone; non-thiazide antihypertensive therapy; thiazide
diuretic therapy in combination with any non-thiazide antihypertensive
agent(s); and no antihypertensive use. Antihypertensive exposure was entered
into the model as a time-varying covariate. Estimates of risk were adjusted
for age, sex, race, nursing home residence, number of prescriptions filled,
intensity of physician use, hospitalization history, and year of antihypertensive
treatment initiation. The adjusted relative risk for the initiation of
anti-gout therapy was 1.00 (95% CI, 0.65-1.53) for non-thiazide antihypertensive
therapy alone, 1.99 (95%, CI, 1.21-3.26) for thiazide diuretic therapy,
and 2.29 (95% CI, 1.55-3.37) for thiazide diuretic therapy in combination
with any non-thiazide agent(s). Risk for anti-gout therapy was significantly
increased for thiazide doses of > or = 25 mg/day (in hydrochlorothiazide
equivalents); no significant increase in risk was seen for lower doses.
We conclude that use of thiazide diuretics in doses of 25 mg/day or higher
is associated with a significantly increased risk for initiation of anti-gout
therapy. Such treatment may reflect the occurrence of clinical sequelae
of diuretic-induced hyperuricemia or the inappropriate treatment of asymptomatic
hyperuricemia.
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Abstract
Many physicians prescribe more than one antiulcerative agent (AUA)
simultaneously to the same patient, although there is little evidence to
support this practice. The purposes of this study were to (a) determine
patient factors associated with the concurrent use of these agents and
(b) estimate the excess costs generated by the prescription of multiple
rather than a single agent. We conducted a case-control study of concurrent
AUA users among New Jersey Medicaid enrollees age 65 years and older. To
evaluate the excess cost generated by the ongoing prescription of an additional
AUA, we measured the additional drug expenditures associated with each
regimen of concurrent use. Nearly 1 in 15 AUA users (6.6%) met our conservative
definition of concurrent AUA use. In a multiple logistic regression model,
previous gastrointestinal procedure, use of a nonsteroidal anti-inflammatory
drugs, nursing home residency, and recent hospitalization for more than
20 days were all predictors of concurrent use of more than one AUA. No
association was found with age, sex, or number of pharmacies used. The
upper bound estimate of the cost generated by the concurrent prescription
of a second AUA was $210 (range: $2-$942) over the 180-day study period,
with a lower bound of $151 (range: $1-$449). Annually, such excess cost
would range from $301 to $420 per patient. This would account for between
$457 million and $637 million per year for the nation's elderly if these
patterns are generalizable. Despite the lack of evidence of therapeutic
benefit from multiple concurrent AUA use in most patients, this practice
is fairly common. Besides introducing the risk of additional costs and
side effects in the absence of additional efficacy, the costs of such duplicative
prescribing are substantial.
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Abstract
BACKGROUND: The prevalence of atrial fibrillation (AF) increases dramatically
with advancing patient age, and, as a result, this condition is common
in persons residing in the long-term care setting.
OBJECTIVES: To assess the knowledge and attitudes of physicians regarding
the use of warfarin for stroke prevention in patients with atrial fibrillation
in long-term care facilities.
METHODS: We surveyed physicians actively providing primary care to
older patients in 30 long-term care facilities located in New England,
Quebec, and Ontario. Physicians were requested to complete a structured
questionnaire about use of warfarin therapy for stroke prevention in patients
with AF residing in long-term care facilities. The questionnaire included
two clinical scenarios designed to provide substantial contrasts in patient
characteristics including underlying comorbidity, functional status, bleeding
risk, and stroke risk.
RESULTS: A total of 269 physicians were asked to participate in the
survey, and 182 (67.7%) completed the questionnaire between February 1,
1995, and July 31, 1995. Only 47% of respondents indicated that the benefits
of warfarin therapy "greatly outweigh the risks" in this setting; the remainder
of physicians indicated that benefits only "slightly outweigh the risks"
(34%) or that risks "outweigh benefits" (19%). The most frequently cited
contraindications to warfarin use were: excessive risk of falls (71%),
history of gastrointestinal bleeding (71%), history of other non-central
nervous system bleeding (36%), and history of cerebrovascular hemorrhage
(25%). Among the 164 physicians who reported using the international normalized
ratio to monitor warfarin therapy, 27% indicated a target range with a
lower limit less than 2, 71% indicated a target range between 2 and 3,
and 2% indicated an upper limit greater than 3. Among respondents who answered
questions about the two clinical scenarios, estimates of the risk of a
stroke without warfarin therapy and the risk of an intracranial hemorrhage
with therapy varied widely.
CONCLUSIONS: Our findings suggest that many uncertainties surround
the decision to prescribe warfarin to patients with AF in the long-term
care setting, as well as questions about the appropriate intensity of this
treatment when it is prescribed. Concerns about the risks of bleeding appear
to prevail over stroke prevention when physicians make such prescribing
decisions.
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The effects of initial drug choice and comorbidity on antihypertensive therapy compliance: results from a population-based study in the elderly. American Journal of Hypertension. 1997;10(7):697-704.
Abstract
Approximately half of all elderly patients have elevated blood pressure,
and proper treatment of this disorder leads to decreased cardiovascular
morbidity in patients 65 and older. This study examined the effect of initial
drug choice and comorbidity on medication compliance. We conducted a retrospective
follow-up of 8643 outpatients aged 65 to 99 with newly prescribed antihypertensive
therapy (AHT) from 1982 to 1988 in the New Jersey Medicaid and Medicare
programs. Compliance was measured in terms of the number of days in which
AHT was available to the patient during the 12 months following the initiation
of therapy. Odds ratios (OR) and 95% confidence intervals (CI) for the
outcome of good compliance (> or =80%) were calculated. In a logistic regression
model, good compliance (> or =80%) was significantly associated with use
of newer agents such as angiotensin converting enzyme inhibitors (OR 1.9,
95% CI 1.6 to 2.2) and calcium channel blockers (OR 1.7, 95% CI 1.5 to
2.1) as compared to thiazides, the presence of comorbid cardiac disease
(OR 1.2, 95% CI 1.1 to 1.2), and multiple physician visits (OR 2.2, 95%
CI 1.8 to 2.5). Good compliance was inversely associated with use of multiple
pharmacies (OR 0.4, 95% CI 0.4 to 0.5) and number of medications prescribed
overall (OR 0.8, 95% CI 0.7 to 0.9). Drug choice, comorbidity, and health
services utilization were significantly associated with AHT compliance
and represent important considerations in the management of high blood
pressure. Noncompliance may be an important cause of treatment failure
in elderly hypertensives.
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Abstract
This study examined the relation between bowel-related symptoms and
self-report of constipation in 10,875 subjects aged 60 years and over,
who participated in the 1989 National Health Interview Survey. Subjects
reporting constipation "always" or "mostly" over the past 12 months (n
= 594) were compared with those who reported never having the symptom (n
= 4,192). Straining (adjusted odds ratio 66.7; 95% confidence interval
31.5, 142.4) and hard bowel movements (25.6; 16.7, 38.7) were most strongly
associated with self-report of constipation. These findings suggest that
treatment for constipation in the older population should be directed as
much or more at facilitating comfortable rectal evacuation, as increasing
bowel movement frequency.
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Abstract
BACKGROUND: While the benefits of warfarin sodium therapy for stroke
prevention in patients with atrial fibrillation (AF) have been extensively
documented, generalizing clinical trial results to the majority of elderly
persons with AF, especially to those who reside in the long-term care setting,
remains challenging.
OBJECTIVES: To determine the prevalence of AF in the institutionalized
elderly population and the proportion receiving anticoagulation therapy
with warfarin: to identify the clinical and functional characteristics
of institutionalized elderly persons with AF that are associated with the
use of warfarin; and to assess the quality of prescribing and monitoring
of warfarin therapy in institutionalized elderly persons with AF.
METHODS: This study involved 30 long-term care facilities (total No.
of beds, 6437) located in New England, Quebec, and Ontario. The proportion
of patients with AF who were receiving treatment with warfarin was
determined. The association between clinical and functional characteristics
and the use of warfarin was examined with crude and multivariable-adjusted
analyses. For study subjects with at least 2 weeks of warfarin therapy
during the 12-month period preceding the date of medical record abstraction,
we assessed the quality of warfarin prescribing based on all international
normalized ratio or prothrombin time ratio values during this period.
RESULTS: An electrocardiogram indicating AF was present in the records
of 413 of 5500 long-term care residents (7.5%); 32% of such patients were
being treated with warfarin. Only a history of stroke was found to be positively
associated with the use of warfarin in this setting. Patients with a diagnosis
of dementia and those in the oldest age group (> or = 85 years) were less
likely to receive warfarin therapy. Warfarin was commonly prescribed to
patients with a history of bleeding, substantial comorbidity and functional
impairment, a history of falls, or concomitant potentiating drug therapy.
Patients were maintained above or below the recommended therapeutic range
60% of the time.
CONCLUSIONS: Atrial fibrillation is common in patients residing in
long-term care facilities, but its management with warfarin is highly variable.
A more systematic approach to decision making regarding the use of warfarin
for stroke prevention in these patients is required. Among patients receiving
warfarin, the quality of anticoagulation care warrants improvement.
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Abstract
OBJECTIVES: The authors assess the costs associated with treatment
of dyspepsia with histamine2 antagonists versus without availability of
over-the-counter (OTC).
METHODS: A cost analysis was performed using a decision-analysis model.
Patients with an initial episode of dyspepsia were studied. The model includes
costs associated with consumption of OTC and prescription (Rx) medications
for dyspepsia, physician visits and associated diagnostic testing, time
spent for physician visits and diagnostic tests, and hospitalization costs.
RESULTS: The model is sensitive to the relative cost of histamine2
antagonists when purchased Rx or OTC, as well as to the efficacy of these
drugs in relieving dyspeptic symptoms. For patients with nonulcer dyspepsia
(the largest group of likely consumers), the model demonstrates a cost
savings if the OTC cost of the medication is slightly less than one third
the Rx cost. Costs are similar whether or not histamine2 antagonists are
available OTC. If the symptom relief efficacies of histamine2 antagonists
are equivalent whether purchased by prescription only or OTC, then the
health-care expenditures for a typical patient with dyspepsia are $204
for OTC availability and $203 for Rx-only use. Viewing costs from the perspective
of a managed-care organization, expenditures for an episode of dyspepsia
are $149 regardless of whether or not histamine2 antagonists are available
OTC. Restricting the analysis to patients with underlying nonulcer dyspepsia
yields similar results. Variation of numerous assumptions and probabilities
other than histamine antagonist cost and efficacy, including costs associated
with physician visits and diagnostic tests, and the likelihood of seeking
medical care, do not substantially affect the results of the model.
CONCLUSIONS: Health-care costs associated with initial treatment of
dyspepsia are similar regardless of the availability of histamine2 antagonists
OTC. This is due largely to the similar efficacy of these drugs compared
with antacids and the predicted increase in diagnostic testing that may
result if a patient visits a physician after failure to achieve symptom
relief with OTC use of histamine2 antagonists.
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Abstract
OBJECTIVE: The objective of this study was to examine how often treatment
for hyperlipidemia followed the use of thiazides, compared with the use
of other antihypertensive drugs, in older patients.
DESIGN: Retrospective follow-up of all health claims filed over a 12-month
period.
SETTING: New Jersey Medicaid and Medicare programs.
PARTICIPANTS: A total of 9274 enrollees, aged 65 to 99, who were newly
initiated on antihypertensive medications from 1981-1989.
MEASUREMENTS: We measured rates of lipid-reducing agent (LRA) initiation
among patients in the 2 years following antihypertensive initiation (thiazide,
non-thiazide drug, or combinations of the two) compared with rates among
patients not currently taking antihypertensive agents. We used Cox regression
analyses to estimate relative risks (RR), accounting for switching in antihypertensive
therapy and for time when drug therapy was not currently available according
to pharmacy refill records.
RESULTS: There were 226 patients (2.4%) in the cohort who were started
on LRA during the follow-up period. After adjusting for potential confounders,
we found no significant relationship between LRA initiation and overall
thiazide use (RR 1.47, 95% CI 0.89-2.40), or other antihypertensive use,
relative to no current exposure. However, use of high-dose thiazides (>
or = 50 mg) was associated significantly with LRA initiation (RR 1.97,
95% CI 1.12-3.45). Factors associated with decreased incidence of LRA use
included age > or = 85 (RR 0.59, 95% CI 0.36-0.96), black race (RR 0.58,
95% CI 0.37-0.91), and nursing home residency (RR 0.20, 95% CI 0.11-0.35).
CONCLUSION: Use of low-cost and effective thiazide diuretics in older
hypertensives was not associated with more common initiation of lipid-reducing
agents, except with high-dose use of thiazides currently seen as inappropriate
in most cases. Age and race were important determinants of LRA use.
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Abstract
Standard cohort and case-control designs are suited to the study of
cumulative effects of chronic exposures, but they are prone to confounding
by indication. Case-crossover and case-time-control studies are especially
useful for studying intermittent exposures with transient effects, and
are less susceptible to confounding by indication. Each design has its
strengths and weaknesses. Despite the increasing availability of automated
databases, cohort studies are usually time consuming and expensive, and
therefore not preferred for time-critical decisions. In case-control studies,
the selection of appropriate controls can be difficult and time consuming,
and sometimes impractical when the exposure is rare. Case-crossover studies
use the exposure history of each case as his or her own control to examine
the effect of transient exposures on acute events. It further allows to
study the time relationship of immediate effects to the exposure. This
design eliminates between-person confounding by constant characteristics,
including chronic indications. Because exposure data for the case and control
periods are provided by the same person, the problems of differential recall
may be reduced in many but not all case-crossover studies. Bias can result
from temporal changes in prescribing or within-person confounding, including
transient indication or changes in disease severity. The case-time-control
design is an elaboration of the case-crossover design, which uses exposure
history data from a traditional control group to estimate and adjust for
the bias from temporal changes in prescribing.
This paper will present a structured decision table of when to use
which design in pharmacoepidemiologic research.
In conclusion, case-crossover and case-time-control studies
are the designs of choice when separating acute effects from chronic effects
of transient exposures and if confounding by indication is an outstanding
problem.
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Abstract
Objective, This case-control study investigated the protective efficacy
against pertussis of three doses of a two-component acellular pertussis
vaccine (manufactured by Biken in Japan) combined with diphtheria and tetanus
toxoids (manufactured by Connaught Laboratories in the US) in infants.
Methods, A case-control study was performed in 63 pediatric practices
in Germany, Prospective recruitment of 16 780 infants ages 6 to 17 weeks
took place between February, 1993, and July, 1994. According to parental
choice infants received either Biken acellular pertussis vaccine combined
with diphtheria and tetanus toxoids (DTacP) (74.6%) at similar to 2, 4
and 6 months of age, or a licensed German diphtheria-tetanus toxoids-whole
cell pertussis vaccine (10.9%), diphtheria-tetanus toxoids vaccine (12.5%)
or no vaccine (2.0%), Prospective surveillance of pertussis cases between
February, 1993, and May, 1995, was accomplished by culturing all infants
less than or equal to 2 years of age presenting with cough greater than
or equal to 7 days, A pertussis case was defined as any cough of 21 days
or longer plus a positive Bordetella pertussis culture or household contact
exposure.
Results, We identified 241 pertussis cases prospectively by 11 017
B. pertussis cultures and 949 controls matched for age were selected from
the same pediatric practices, Medical history and demographic and vaccine
status data were collected from each case and for four controls, Data were
analyzed through conditional logistic regression taking into account individual
matching and adjusting for potential confounding variables, DTacP combined
with diphtheria and tetanus toxoids vaccine was 82% protective (95% confidence
interval, 68 to 90), diphtheria-tetanus toxoids whole cell pertussis vaccine
was 96% protective (95% confidence interval, 78 to 99). Protection against
typical B. pertussis infection characterized by paroxysmal cough lasting
greater than or equal to 21 days was 96% (95% confidence interval, 87 to
99) for DTacP and was 97% (95% confidence interval, 79 to 100) for diphtheria-tetanus
toxoids-whole cell pertussis vaccine, Adjustment for potentially confounding
variables did not change the results significantly.
Conclusions. Three doses of the two-component acellular pertussis vaccine
protected infants against pertussis disease during the period before the
recommended booster vaccination. For typical pertussis disease as defined
by the WHO efficacy was high and similar to that of a licensed German diphtheria-tetanus
toxoids-whole cell pertussis vaccine.
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