Highlights and a hidden hazard--the FDA's new labeling regulations.
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Biomedical subjects
Publications and source records attributed to Jerry Avorn.
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OBJECTIVE: Observational studies have found beneficial effects of lipid-lowering drugs on diverse outcomes, including venous thromboembolism, hip fracture, dementia, and all-cause mortality. Selective use of these drugs in frail people may confound these relationships. STUDY DESIGN AND SETTING: We measured 1-year mortality in two cohorts of New Jersey residents, aged 65-99 years, enrolled in state-sponsored drug benefits programs: 112,463 persons hospitalized during the years 1991-1994 and 106,838 nonhospitalized enrollees. Use of lipid-lowering drugs and other medications, as well as diagnoses, were evaluated before follow-up. RESULTS: In age- and sex-adjusted analyses, users of lipid-lowering drugs had a 43% reduced death rate relative to nonusers among hospitalized enrollees and a 56% reduction in the nonhospitalized sample. Available markers of frailty and comorbidity predicted decreased use of these drugs. Control for the propensity to use lipid-lowering drugs attenuated but did not eliminate these effects. After such adjustment, users had a 30% reduction in death rate (95% confidence interval [CI]: 25%-35%) among hospitalized enrollees and a 41% reduction (95% CI: 35%-47%) in the nonhospitalized sample. Unmeasured frailty associated with a 26%-33% reduced odds of receiving lipid-lowering therapy could explain this effect. CONCLUSION: Frailty and comorbidity that influence use of preventive therapies can substantially confound apparent benefits of lipid-lowering drugs on outcomes.
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Despite the growing popularity of propensity score (PS) methods in epidemiology, relatively little has been written in the epidemiologic literature about the problem of variable selection for PS models. The authors present the results of two simulation studies designed to help epidemiologists gain insight into the variable selection problem in a PS analysis. The simulation studies illustrate how the choice of variables that are included in a PS model can affect the bias, variance, and mean squared error of an estimated exposure effect. The results suggest that variables that are unrelated to the exposure but related to the outcome should always be included in a PS model. The inclusion of these variables will decrease the variance of an estimated exposure effect without increasing bias. In contrast, including variables that are related to the exposure but not to the outcome will increase the variance of the estimated exposure effect without decreasing bias. In very small studies, the inclusion of variables that are strongly related to the exposure but only weakly related to the outcome can be detrimental to an estimate in a mean squared error sense. The addition of these variables removes only a small amount of bias but can increase the variance of the estimated exposure effect. These simulation studies and other analytical results suggest that standard model-building tools designed to create good predictive models of the exposure will not always lead to optimal PS models, particularly in small studies.
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The objective of this work was to assess the convergent validity of a previously developed rheumatoid arthritis medical records-based index of severity (RARBIS) by comparing it with the 28-joint Disease Activity Score (DAS28). This study was conducted in subjects within the Brigham and Women's Hospital Rheumatoid Arthritis Sequential Study (BRASS). We selected 100 patients with rheumatoid arthritis (RA) from the BRASS with DAS28 scores equally distributed in four quartiles. The medical records were reviewed to calculate the RARBIS, which includes indicators from the following categories: prior surgical history, radiologic and laboratory findings, clinical and functional status, and extra-articular manifestations. The Spearman correlation between the RARBIS and the DAS28 was assessed in the total study population and in relevant subgroups. We re-weighted on subscales and recalculated the RARBIS score. This was performed based on findings of correlations between the DAS28 and subscales; and also the result from a multiple linear regression with the DAS28 (as a dependent variable) and five subscales (as independent variables). The mean RARBIS was 4.36 (range 0-11). Among the total study cohort, the RARBIS was moderately correlated with the DAS28 (r = 0.41, 95% confidence interval [CI] 0.23-0.56). In subgroup analyses, including age, gender, rheumatoid factor status, and disease duration, we found no statistically significant differences in the correlations. After re-weighting, the correlation between the RARBIS and the DAS28 was somewhat improved (r = 0.48, 95% CI 0.31-0.62). In conclusion, the RARBIS correlated moderately well with the DAS28 in this population. The RARBIS has both face and convergent validity for patients with RA and relevant subgroups and may have application for medical records studies in patients with RA.
OBJECTIVE: To examine patterns of chronic opioid use in selected groups with arthritis and low back pain and compare them with patterns among persons with ischemic heart disease. METHODS: The study database consisted of Medicare beneficiaries who were enrolled in a drug benefit program for low-to-moderate income Pennsylvania residents. We identified selected patients who had a diagnosis of rheumatoid arthritis, osteoarthritis, chronic low back pain, or ischemic heart disease since 1995. Chronic opioid use, defined as at least six 30-day prescriptions in a year, was the endpoint of interest. We examined the proportion of patients meeting this definition during the period 1996-2001 and determined predictors based on multivariable Cox proportional hazards models. RESULTS: Four percent of subjects with rheumatoid arthritis used opioids chronically in 2001, compared with <1% in each of the other groups. There was no increase in the chronic use of opioids over the 6-year study period. Low-potency opioids were the most commonly prescribed preparations for chronic users from all patient groups. The prior use of medicines for psychiatric illness, including benzodiazepines or barbiturates, was associated with chronic prescription opioid use across all diagnoses. However, subjects with a prior diagnosis of psychiatric illness were less likely to receive chronic opioids. CONCLUSION: Chronic opioid use is relatively uncommon, even among older individuals with arthritis or low back pain. The proportion of these individuals receiving such medicines has not increased in the late 1990s. There seems to be a complex relationship between psychiatric medication use, psychiatric diagnoses, and the use of chronic opioids among these individuals.
BACKGROUND: A large proportion of Americans are enrolled in 3-tier pharmacy benefit plans. We studied whether patients enrolled in such plans who receive generic or preferred brand-name agents when initiating chronic therapy were more adherent to treatment than those who received nonpreferred brand-name medications. METHODS: We analyzed pharmacy claims filled between October 1, 2001, and October 1, 2003, from a large health plan for 6 classes of chronic medications: 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors, calcium channel blockers, oral contraceptives, orally inhaled corticosteroids, angiotensin receptor blockers, and angiotensin-converting enzyme inhibitors. We measured adherence as the proportion of days covered (PDC) in each drug class during the first year of therapy. We evaluated how the formulary status of the initial prescription (generic, preferred, or nonpreferred) influenced PDC and adequate adherence, defined as PDC greater than 80%, over the subsequent year. RESULTS: A total of 7532 new prescriptions were filled in 1 of the classes evaluated: 1747 (23.2%) for nonpreferred medications, 4376 (58.1%) for preferred drugs, and 1409 (18.7%) for generic drugs. After controlling for patient sociodemographic characteristics and drug class, PDC was 12.6% greater for patients initiated on generic medications vs nonpreferred medications (58.8% vs 52.2%; P<.001). The PDC was 8.8% greater for patients initiated on preferred vs nonpreferred medications (56.8% vs 52.2%; P<.001). Patients initiated on generic and preferred medications had 62% and 30% greater odds, respectively, of achieving adequate adherence compared with those who received nonpreferred medications. CONCLUSION: In 3-tier pharmacy benefit plans, prescribing generic or preferred medications within a therapeutic class is associated with improvements in adherence to therapy.
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Medication-attributed adverse effects are a frequent reason for poor compliance in practice and in clinical studies and are also common in patients receiving placebo. The occurrence of adverse effects in placebo groups can clarify the assessment of adverse event reporting. We analyzed data from randomized, placebo-controlled trials of statin drugs published since 1992 with sample sizes larger than 100 subjects. Reports of adverse effects and discontinuation rates in placebo groups were evaluated. We compared data on adverse effect profiles in placebo groups between trials and with expected rates from population-based studies. We also sought to determine the range of adverse effect ascertainment methods used in different studies. Methods of ascertainment of adverse events varied widely across studies. Overall, 4% to 26% of patients in the control groups of large trials of statin drugs discontinued placebo use because of perceived adverse effects. The symptom rate in placebo groups varied substantially across trials (up to a ratio of 13:1 for possibly drug-related symptoms, eg, headache, 0.2%-2.7%, or abdominal pain, 0.9%-3.9%) and were often markedly lower than those found in the general population (eg, fatigue, 1.9%-3.4%) in trials of statin drugs vs 17.7% in the general population. In conclusion, the widely varying rates of adverse effects reported by patients taking placebo and the high prevalence of such symptoms in the general population should be considered by both trialists and clinicians. In addition, variability of adverse effect ascertainment is considerable and suggests the need for better standardization in research.
OBJECTIVE: Controversy persists regarding the cardiovascular risks of treatment with selective cyclooxygenase 2 inhibitors (coxibs) and nonselective nonsteroidal antiinflammatory drugs (NSAIDs). This study was undertaken to examine, in a large group of new users of coxibs and NSAIDs, the rate of cardiovascular events, their time course, and whether baseline cardiovascular risk modified the rate ratios (RRs) for future events. METHODS: This cohort study included Medicare beneficiaries who enrolled in a state-run prescription drug plan that fully covered NSAIDs and coxibs without restriction. All study patients started use of a coxib or NSAID after January 1, 1999. The primary composite end point was a hospital admission for either myocardial infarction or ischemic stroke. Predefined exposure groups included the 3 coxibs available in the US during the study period (celecoxib, rofecoxib, and valdecoxib), as well as oral formulations of diclofenac, ibuprofen, naproxen, and a composite of all other NSAIDs. We compared the rate of cardiovascular events associated with each of these agents with that in a reference group of patients who did not use NSAIDs or coxibs, but started other medications unrelated to cardiovascular risk. Daily exposure to all study drugs was assessed based on filled prescription data. A Cox proportional hazards model stratified on calendar year that included other baseline cardiovascular risk factors constituted the primary analysis. RESULTS: We identified 74,838 users of NSAIDs or coxibs, and 23,532 comparable users of other drugs comprised the reference group. Adjusted models demonstrated a significant elevation in the event rate for rofecoxib (RR 1.15, 95% confidence interval [95% CI] 1.06-1.25) and a significant reduction in the rate for naproxen (RR 0.75, 95% CI 0.62-0.92). No other coxib or NSAID was associated with a significant increase or decrease in cardiovascular event rate. The increased rate associated with rofecoxib was seen in the first 60 days of use (adjusted RR 1.14, 95% CI 1.01-1.29) and thereafter (adjusted RR 1.14, 95% CI 1.02-1.28). Kaplan-Meier event curves showed a similar pattern of risk (early and persistent separation of the event curves) among long-term rofecoxib users at low or high baseline cardiovascular risk. CONCLUSION: We found an increased cardiovascular event rate among users of rofecoxib, and a decreased rate with naproxen use. Other coxibs and NSAIDs did not appear to be associated with a difference in event rate compared with users of other drugs. The increase in rate associated with rofecoxib was seen within the first 60 days and persisted. There was no important modification of the event rate based on the patient's baseline cardiovascular risk.
OBJECTIVE: Concerns persist about a possible association between tumor necrosis factor alpha (TNFalpha) antagonist treatment and development of cancers in patients with rheumatoid arthritis (RA). This study was undertaken to estimate the association between treatment with biologic disease-modifying antirheumatic drugs (DMARDs) and development of cancer in patients with RA. METHODS: We conducted a cohort study pooling administrative databases from 2 US states and 1 Canadian province. A cohort of patients who had received a diagnosis of RA on > or =1 occasion and had been prescribed DMARDs was identified. We categorized patients with a prescription for a biologic DMARD as biologic DMARD users, and those with a prescription for methotrexate (MTX) but no biologic DMARD as MTX users. We used time-varying propensity scores to adjust for the large number of possible confounders and stratified proportional hazards regression to estimate the effects of biologic DMARDs on cancer. The primary end points were hematologic malignancies (lymphoma, multiple myeloma, and leukemia) and common solid tumors (colorectal, lung, stomach, breast, prostate, uterine, ovarian, urinary tract/bladder, and melanoma). RESULTS: The pooled cohort included 1,152 biologic DMARD users and 7,306 MTX users. We identified 11 hematologic malignancies and 46 solid tumors during 2,940 person-years of biologic DMARD use, and 88 hematologic malignancies and 558 solid tumors during 30,300 person-years of MTX use. Comparing biologic DMARD users with MTX users, the propensity score-adjusted pooled hazard ratio was 1.37 (95% confidence interval 0.71-2.65) for hematologic malignancies and 0.91 (95% confidence interval 0.65-1.26) for solid tumors. CONCLUSION: Our results indicate that users of biologic agents are unlikely to have a substantial increase in the risk of hematologic malignancies and solid tumors as compared with MTX users. Despite the use of large combined data sets, studying the effect of an infrequent exposure (biologic DMARDs) on rare diseases (hematologic malignancies) remains a challenge.
OBJECTIVE: With the growing need to provide prescription drug benefits to older patients and to contain costs, it will be necessary to direct that coverage so as to make expenditures as efficient as possible. We evaluated the clinical and economic consequences of coverage restriction for 3 leading proton pump inhibitors (PPIs) in a large-scale natural experiment. METHODS: The study design was a time-trend analysis in the setting of a provincial drug benefits program in British Columbia, Canada. We studied all British Columbia residents aged 66 or older (N = 501,104) using linked data on all prescription drug dispensings, physician services, and hospitalizations between January 2002 and June 2004. The new policy restricted coverage to rabeprazole and required treatment failure with a histamine H2 blocker. More widely used PPIs (omeprazole, pantoprazole, and lansoprazole) had to be paid for out of pocket, unless the physician requested an exemption. The main outcome measures were utilization of PPIs, drug discontinuation rates, gastrointestinal hemorrhage rates, and drug expenditures. RESULTS: Utilization of the restricted PPIs declined sharply after the policy change (-14,850 daily doses per month per 10,000 residents, P < .0001), whereas use of the covered PPI increased sharply (+19,300, P < .0001), with 45% of all PPI users switching to the covered agent within 6 months. We found no increased use of H2 blockers or stopping of gastroprotective drugs. There was no increase in the monthly rate of hospitalization for gastrointestinal hemorrhage after the PPI restriction (P = .35) even though the study had the power to detect increases of 24 events per 10,000 residents with 95% confidence. There was a slight increase in physician visits 3 months after the policy change (P = .01) for a 2-month period when 9% of new rabeprazole users were switched back to a restricted PPI. In the first 6 months of the policy change, the provincial health plan saved at least 2.9 million Canadian dollars as a result of the policy change. CONCLUSIONS: Coverage restriction of 3 leading PPIs led to substantial utilization changes and savings, without increased noncompliance or clinical complication.
BACKGROUND: Beta-blockers, statins, angiotensin-converting enzyme (ACE) inhibitors, and angiotensin receptor blockers (ARBs) are standard therapies after myocardial infarction (MI) in the general population. Their use and association with mortality in elderly dialysis patients after MI have not been studied sufficiently. METHODS: Claims records from Medicare and Medicaid patients aged 65 years and older who participated in prescription benefit plans of 2 eastern states were used to identify dialysis patients with MI between 1995 and 2003. Study outcomes were outpatient use of beta-blockers, statins, and ACE inhibitors and/or ARBs within 90 days after MI. We used multivariate logistic regression to assess predictors of such use. Multivariate Cox regression was applied to test for associations between beta-blocker, statin, and ACE-inhibitor and/or ARB use and 1-year mortality. RESULTS: We identified 902 dialysis patients who were hospitalized with MI. Of these, 39.5% died within 90 days and 63.6% died within 1 year after MI. Of 494 patients who were discharged within 21 days or less and survived longer than 90 days, 31.0% were administered an ACE inhibitor and/or ARB; 19.4%, a statin; and 34.2%, a beta-blocker after discharge. Use of ACE inhibitors and/or ARBs was associated with a 30% reduction in 1-year mortality (hazard ratio [HR], 0.70; 95% confidence interval [CI], 0.50 to 0.98), whereas statin (HR, 0.97; 95% CI, 0.65 to 1.45) and beta-blocker use (HR, 1.05; 95% CI, 0.78 to 1.43) were not. CONCLUSION: Elderly dialysis patients have excessively high mortality and low use of standard therapies after MI. Only ACE inhibitors and/or ARBs were associated with a reduced risk for death at 1 year in this population. Whether the high mortality rate in this population is attributable to such low use of preventive cardiovascular medications remains uncertain.
BACKGROUND: Many state Medicaid programs use prior authorization programs to limit spending on cyclooxygenase-2 selective nonsteroidal anti-inflammatory drugs (coxibs). However, the evidence base for the prior authorization criteria has not been examined previously. METHODS: We determined whether prior authorization was required for coxibs in state Medicaid programs and collected data on what precise criteria needed to be met for a coxib prescription to be authorized. Prior authorization criteria were compared to clinical evidence regarding which patients are most likely to benefit from coxibs. RESULTS: By mid-2004, 35 states had implemented prior authorization requirements for coxibs. Of 5 major clinical factors that identify patients likely to benefit from coxibs, 18 states (51%) included all 5 factors and 9 states (26%) included 2 or fewer. Most states (33/35; 94%) required a previous trial of nonselective nonsteroidal anti-inflammatory drugs before a coxib would be authorized. Several prior authorization programs included factors that had no connection to the clinical evidence. CONCLUSIONS: State Medicaid prior authorization policies for coxibs are heterogeneous in terms both of the criteria required to obtain a coxib and of the relationship of those criteria to clinical evidence. Development of clinically rational prescription drug policies should be a goal for all health insurers and represents an important priority for Medicare's prescription drug benefit program.
BACKGROUND: Angiotensin converting enzyme-inhibitors (ACEI) and angiotensin-II-receptor blockers (ARB) are equally efficacious in reducing mortality after MI, although the latter are far more costly. Little is known about their relative use after MI in typical care settings, and about their relative effectiveness outside the clinical trial setting. OBJECTIVES: To assess temporal trends in the relative use of ACEI and ARB after myocardial infarction, and to test for differences in 1-year survival between users of these drug classes. DESIGN: Retrospective closed cohort study. PATIENTS: Medicare beneficiaries who survived >90 days after myocardial infarction, had full prescription drug coverage, and who filled a prescription for either ACEI or ARB within 90 days of myocardial infarction. MEASUREMENTS: Relative use of ACEI versus ARB over time. Adjusted relative 1-year mortality between ACEI and ARB users. RESULTS: Between 1995 and 2004, 14,190 patients met inclusion criteria. Mean age was 80 years, 75% were female, and 90% were white. Overall, 88% received an ACEI, and 12% an ARB, with the proportion receiving an ARB increasing from 2% (1995) to 25% (2004; P<.001). Multivariate-adjusted 1-year mortality did not differ between ARB and ACEI users (HR: 1.04; 95% confidence interval: 0.88 to 1.22). The findings were similar for new users of ACEI/ARB, and for those with preexisting heart failure. CONCLUSIONS: ARB users had the same 1-year mortality after myocardial infarction as ACEI users in routine care. Use of more costly ARB has increased dramatically over time, to a quarter of ACEI/ARB users, despite the lack of a therapeutic advantage for most patients.
OBJECTIVE: While national guidelines recommend ACE inhibitor (ACEI) or angiotensin receptor blocker (ARB) therapy in patients with diabetes and nephropathy, guidelines concerning elderly patients with diabetes have not endorsed these drugs. We sought to assess the nephroprotective efficacy and safety of ARB therapy in elderly patients by conducting age-specific subgroup analyses using data from the Reduction of Endpoints in NIDDM with the Angiotensin II Antagonist Losartan (RENAAL) study. RESEARCH DESIGN AND METHODS: We studied 1,513 patients with type 2 diabetes and nephropathy who randomly received either losartan or placebo. We tested for effect modification by age of the effect of losartan on the incidence of the predefined end points (doubling of serum creatinine, end-stage renal disease [ESRD], or death) and the risk of adverse events. RESULTS: Of 1,513 participants, 421 (27.8%) were aged >65 years (maximum age 74 years). Age did not modify the efficacy of losartan in reducing the risk of the primary outcome, a composite of doubling of serum creatinine, ESRD, or death (P(interaction) = 0.66) or its individual components (all P(interaction) > 0.44). In patients aged >65 years, losartan reduced the risk of ESRD by 50% (95% CI 30-81, P = 0.005). We found no evidence that older patients were more likely to experience adverse events from losartan such as a rise in serum creatinine or hyperkalemia than younger patients. CONCLUSIONS: Elderly patients had the same level of benefits and risks as younger patients from treatment with losartan. Underuse of ACEI and ARB therapy in elderly patients because of the perceived lack of efficacy or a greater risk of adverse events appears unjustified.
BACKGROUND: Recently, the Food and Drug Administration (FDA) issued an advisory stating that atypical antipsychotic medications increase mortality among elderly patients. However, the advisory did not apply to conventional antipsychotic medications; the risk of death with these older agents is not known. METHODS: We conducted a retrospective cohort study involving 22,890 patients 65 years of age or older who had drug insurance benefits in Pennsylvania and who began receiving a conventional or atypical antipsychotic medication between 1994 and 2003. Analyses of mortality rates and Cox proportional-hazards models were used to compare the risk of death within 180 days, less than 40 days, 40 to 79 days, and 80 to 180 days after the initiation of therapy with an antipsychotic medication. We controlled for potential confounding variables with the use of traditional multivariate Cox models, propensity-score adjustments, and an instrumental-variable analysis. RESULTS: Conventional antipsychotic medications were associated with a significantly higher adjusted risk of death than were atypical antipsychotic medications at all intervals studied (< or =180 days: relative risk, 1.37; 95 percent confidence interval, 1.27 to 1.49; <40 days: relative risk, 1.56; 95 percent confidence interval, 1.37 to 1.78; 40 to 79 days: relative risk, 1.37; 95 percent confidence interval, 1.19 to 1.59; and 80 to 180 days: relative risk, 1.27; 95 percent confidence interval, 1.14 to 1.41) and in all subgroups defined according to the presence or absence of dementia or nursing home residency. The greatest increases in risk occurred soon after therapy was initiated and with higher dosages of conventional antipsychotic medications. Increased risks associated with conventional as compared with atypical antipsychotic medications persisted in confirmatory analyses performed with the use of propensity-score adjustment and instrumental-variable estimation. CONCLUSIONS: If confirmed, these results suggest that conventional antipsychotic medications are at least as likely as atypical agents to increase the risk of death among elderly persons and that conventional drugs should not be used to replace atypical agents discontinued in response to the FDA warning.