Jessica M. Franklin

Antidepressant Use in Pregnancy and the Risk of Cardiac Defects

BACKGROUND Whether the use of selective serotonin-reuptake inhibitors (SSRIs) and other antidepressants during pregnancy is associated with an increased risk of congenital cardiac defects is uncertain. In particular, there are concerns about a possible association between paroxetine use and right ventricular outflow tract obstruction and between sertraline use and ventricular septal defects. METHODS We performed a cohort study nested in the nationwide Medicaid Analytic eXtract for the period 2000 through 2007. The study included 949,504 pregnant women who were enrolled in Medicaid during the period from 3 months before the last menstrual period through 1 month after delivery and their liveborn infants. We compared the risk of major cardiac defects among infants born to women who took antidepressants during the first trimester with the risk among infants born to women who did not use antidepressants, with an unadjusted analysis and analyses that restricted the cohort to women with depression and that used propensity-score adjustment to control for depression severity and other potential confounders. RESULTS A total of 64,389 women (6.8%) used antidepressants during the first trimester. Overall, 6403 infants who were not exposed to antidepressants were born with a cardiac defect (72.3 infants with a cardiac defect per 10,000 infants), as compared with 580 infants with exposure (90.1 per 10,000 infants). Associations between antidepressant use and cardiac defects were attenuated with increasing levels of adjustment for confounding. The relative risks of any cardiac defect with the use of SSRIs were 1.25 (95% confidence interval [CI], 1.13 to 1.38) in the unadjusted analysis, 1.12 (95% CI, 1.00 to 1.26) in the analysis restricted to women with depression, and 1.06 (95% CI, 0.93 to 1.22) in the fully adjusted analysis restricted to women with depression. We found no significant association between the use of paroxetine and right ventricular outflow tract obstruction (relative risk, 1.07; 95% CI, 0.59 to 1.93) or between the use of sertraline and ventricular septal defects (relative risk, 1.04; 95% CI, 0.76 to 1.41). CONCLUSIONS The results of this large, population-based cohort study suggested no substantial increase in the risk of cardiac malformations attributable to antidepressant use during the first trimester. (Funded by the Agency for Healthcare Research and Quality and the National Institutes of Health.).

Group-based Trajectory Models A New Approach to Classifying and Predicting Long-Term Medication Adherence

Background:Classifying medication adherence is important for efficiently targeting adherence improvement interventions. The purpose of this study was to evaluate the use of a novel method, group-based trajectory models, for classifying patients by their long-term adherence. Research Design:We identified patients who initiated a statin between June 1, 2006 and May 30, 2007 in prescription claims from CVS Caremark and evaluated adherence over the subsequent 15 months. We compared several adherence summary measures, including proportion of days covered (PDC) and trajectory models with 2–6 groups, with the observed adherence pattern, defined by monthly indicators of full adherence (defined as having ≥24 d covered of 30). We also compared the accuracy of adherence prediction based on patient characteristics when adherence was defined by either a trajectory model or PDC. Results:In 264,789 statin initiators, the 6-group trajectory model summarized long-term adherence best (C=0.938), whereas PDC summarized less well (C=0.881). The accuracy of adherence predictions was similar whether adherence was classified by PDC or by trajectory model. Conclusions:Trajectory models summarized adherence patterns better than traditional approaches and were similarly predicted by covariates. Group-based trajectory models may facilitate targeting of interventions and may be useful to adjust for confounding by health-seeking behavior.

Matching by Propensity Score in Cohort Studies with Three Treatment Groups

Background: Nonrandomized pharmacoepidemiology generally compares one medication with another. For many conditions, clinicians can benefit from comparing the safety and effectiveness of three or more appropriate treatment options. We sought to compare three treatment groups simultaneously by creating 1:1:1 propensity score-matched cohorts. Methods: We developed a technique that estimates generalized propensity scores and then creates 1:1:1 matched sets. We compared this methodology with two existing approaches—construction of matched cohorts through a common-referent group and a pairwise match for each possible contrast. In a simulation, we varied unmeasured confounding, presence of treatment effect heterogeneity, and the prevalence of treatments and compared each method’s bias, variance, and mean squared error (MSE) of the treatment effect. We applied these techniques to a cohort of rheumatoid arthritis patients treated with nonselective nonsteroidal anti-inflammatory drugs, COX-2 selective inhibitors, or opioids. Results: We performed 1000 simulation runs. In the base case, we observed an average bias of 0.4% (MSE × 100 = 0.2) in the three-way matching approach and an average bias of 0.3% (MSE × 100 = 0.2) with the pairwise technique. The techniques showed differing bias and MSE with increasing treatment effect heterogeneity and decreasing propensity score overlap. With highly unequal exposure prevalences, strong heterogeneity, and low overlap, we observed a bias of 6.5% (MSE × 100 = 10.8) in the three-way approach and 12.5% (MSE × 100 = 12.3) in the pairwise approach. The empirical study displayed better covariate balance using the pairwise approach. Point estimates were substantially similar. Conclusions: Our matching approach offers an effective way to study the safety and effectiveness of three treatment options. We recommend its use over the pairwise or common-referent approaches.

Statins and congenital malformations: cohort study

Objective To examine the teratogenic potential of statins. Design Cohort study. Setting United States. Participants A cohort of 886 996 completed pregnancies linked to liveborn infants of women enrolled in Medicaid from 2000 to 2007. Methods We examined the risk of major congenital malformations and organ specific malformations in offspring associated with maternal use of a statin in the first trimester. Propensity score based methods were used to control for potential confounders, including maternal demographic characteristics, obstetric and medical conditions, and use of other drugs. Results 1152 (0.13%) women used a statin during the first trimester. In unadjusted analyses, the prevalence of malformations in the offspring of these women was 6.34% compared with 3.55% in those of women who did not use a statin in the first trimester (relative risk 1.79, 95% confidence interval 1.43 to 2.23). Controlling for confounders, particularly pre-existing diabetes, accounted for this increase in risk (1.07, 0.85 to 1.37). There were also no statistically significant increases in any of the organ specific malformations assessed after accounting for confounders. Results were similar across a range of sensitivity analyses. Conclusions Our analysis did not find a significant teratogenic effect from maternal use of statins in the first trimester. However, these findings need to be replicated in other large studies, and the long term effects of in utero exposure to statins needs to be assessed, before use of statins in pregnancy can be considered safe.

Trends in utilization of FDA expedited drug development and approval programs, 1987-2014: cohort study

Objective To evaluate the use of special expedited development and review pathways at the US Food and Drug Administration over the past two decades. Design Cohort study. Setting FDA approved novel therapeutics between 1987 and 2014. Population Publicly available sources provided each drug’s year of approval, their innovativeness (first in class versus not first in class), World Health Organization Anatomic Therapeutic Classification, and which (if any) of the FDA’s four primary expedited development and review programs or designations were associated with each drug: orphan drug, fast track, accelerated approval, and priority review. Main outcome measures Logistic regression models evaluated trends in the proportion of drugs associated with each of the four expedited development and review programs. To evaluate the number of programs associated with each approved drug over time, Poisson models were employed, with the number of programs as the dependent variable and a linear term for year of approval. The difference in trends was compared between drugs that were first in class and those that were not. Results The FDA approved 774 drugs during the study period, with one third representing first in class agents. Priority review (43%) was the most prevalent of the four programs, with accelerated approval (9%) the least common. There was a significant increase of 2.6% per year in the number of expedited review and approval programs granted to each newly approved agent (incidence rate ratio 1.026, 95% confidence interval 1.017 to 1.035, P<0.001), and a 2.4% increase in the proportion of drugs associated with at least one such program (odds ratio 1.024, 95% confidence interval 1.006 to 1.043, P=0.009). Driving this trend was an increase in the proportion of approved, non-first in class drugs associated with at least one program for drugs (P=0.03 for interaction). Conclusions In the past two decades, drugs newly approved by the FDA have been associated with an increasing number of expedited development or review programs. Though expedited programs should be strictly limited to drugs providing noticeable clinical advances, this trend is being driven by drugs that are not first in class and thus potentially less innovative.

Metrics for covariate balance in cohort studies of causal effects

Inferring causation from non-randomized studies of exposure requires that exposure groups can be balanced with respect to prognostic factors for the outcome. Although there is broad agreement in the literature that balance should be checked, there is confusion regarding the appropriate metric. We present a simulation study that compares several balance metrics with respect to the strength of their association with bias in estimation of the effect of a binary exposure on a binary, count, or continuous outcome. The simulations utilize matching on the propensity score with successively decreasing calipers to produce datasets with varying covariate balance. We propose the post-matching C-statistic as a balance metric and found that it had consistently strong associations with estimation bias, even when the propensity score model was misspecified, as long as the propensity score was estimated with sufficient study size. This metric, along with the average standardized difference and the general weighted difference, outperformed all other metrics considered in association with bias, including the unstandardized absolute difference, Kolmogorov-Smirnov and Lévy distances, overlapping coefficient, Mahalanobis balance, and L1 metrics. Of the best-performing metrics, the C-statistic and general weighted difference also have the advantage that they automatically evaluate balance on all covariates simultaneously and can easily incorporate balance on interactions among covariates. Therefore, when combined with the usual practice of comparing individual covariate means and standard deviations across exposure groups, these metrics may provide useful summaries of the observed covariate imbalance.

Serious Infections Among Adult Medicaid Beneficiaries With Systemic Lupus Erythematosus and Lupus Nephritis

To examine the epidemiology of serious infections, a significant cause of morbidity and mortality in systemic lupus erythematosus (SLE), in a nationwide cohort of SLE and lupus nephritis (LN) patients.

Type of stress ulcer prophylaxis and risk of nosocomial pneumonia in cardiac surgical patients: cohort study

Objective To examine the relation between the type of stress ulcer prophylaxis administered and the risk of postoperative pneumonia in patients undergoing coronary artery bypass grafting. Design Retrospective cohort study. Setting Premier Research Database. Participants: 21 214 patients undergoing coronary artery bypass graft surgery between 2004 and 2010; 9830 (46.3%) started proton pump inhibitors and 11 384 (53.7%) started H2 receptor antagonists in the immediate postoperative period. Main outcome measure Occurrence of postoperative pneumonia, assessed using appropriate diagnostic codes. Results Overall, 492 (5.0%) of the 9830 patients receiving a proton pump inhibitor and 487 (4.3%) of the 11 384 patients receiving an H2 receptor antagonist developed postoperative pneumonia during the index hospital admission. After propensity score adjustment, an elevated risk of pneumonia associated with treatment with proton pump inhibitors compared with H2 receptor antagonists remained (relative risk 1.19, 95% confidence interval 1.03 to 1.38). In the instrumental variable analysis, use of a proton pump inhibitor (compared with an H2 receptor antagonist) was associated with an increased risk of pneumonia of 8.2 (95% confidence interval 0.5 to 15.9) cases per 1000 patients. Conclusions Patients treated with proton pump inhibitors for stress ulcer had a small increase in the risk of postoperative pneumonia compared with patients treated with H2 receptor antagonists; this risk remained after confounding was accounted for using multiple analytic approaches.

The Risk of Congenital Malformations Associated With Exposure to β-Blockers Early in Pregnancy: A Meta-Analysis

&bgr;-blockers are commonly used during the first trimester of pregnancy. Data about risks of congenital anomalies in offspring have not been summarized. We performed a meta-analysis to determine teratogenicity of &bgr;-blockers in early pregnancy. A systematic literature search was performed using PubMed, EMBASE, Cochrane Clinical Trials, and hand search. Meta-analyses were performed using random-effects models based on odds ratios (ORs). Prespecified subgroup analyses were performed to explore heterogeneity. Randomized controlled trials or observational studies examining risks of congenital malformations associated with first trimester &bgr;-blocker exposure compared with no exposure were included. Thirteen population-based case–control or cohort studies were identified. Based on meta-analyses, first-trimester oral &bgr;-blocker use showed no increased odds of all or major congenital anomalies (OR=1.00; 95% confidence interval, 0.91–1.10; 5 studies). However, in analyses examining organ-specific malformations, increased odds of cardiovascular defects (OR=2.01; 95% confidence interval, 1.18–3.42; 4 studies), cleft lip/palate (OR=3.11; 95% confidence interval, 1.79–5.43; 2 studies), and neural tube defects (OR=3.56; 95% confidence interval, 1.19–10.67; 2 studies) were observed. The effects on severe hypospadias were nonsignificant (1 study). Causality is difficult to interpret given the small number of heterogeneous studies and possibility of biases. Given the frequency of this exposure in pregnancy, further research is needed.

Impact of the U.S. Food and Drug Administration's Safety-Related Announcements on the Use of Bisphosphonates After Hip Fracture

The U.S. Food and Drug Administration (FDA) issued several announcements related to potential risk of bisphosphonates including osteonecrosis of the jaw (2005), atrial fibrillation (2007), and atypical femur fracture (2010). We aimed to evaluate the impact of three FDA drug safety announcements on the use of bisphosphonates in patients with hip fracture using claims data from a U.S. commercial health plan (2004‐2013). We calculated the proportion of patients in each quarter who received a bisphosphonate or other osteoporosis medication in the 6 months following hospitalization for hip fracture. Segmented logistic regression models examined the time trends. Among 22,598 patients with hip fracture, use of bisphosphonate decreased from 15% in 2004 to 3% in the last quarter of 2013. Prior to the 2007 announcement, there was a 4% increase in the odds of bisphosphonate use every quarter (OR 1.04; 95% CI, 1.02 to 1.07). After the 2007 announcement, there was a 4% decrease in the odds of bisphosphonate use (OR 0.96; 95% CI, 0.93 to 0.99) every quarter. The announcement in 2007 was associated with a significant decline in the rate of change of bisphosphonate uses over time (p < 0.001), but no impact on other osteoporosis medication use (p = 0.2). After the 2010 announcement, the odds of bisphosphonate use continued to decrease by 4% (OR 0.96; 95% CI, 0.94 to 0.98) each quarter and the odds of other osteoporosis medication use remained stable over time (OR 0.99; 95% CI, 0.96 to 1.02). The FDA safety announcement related to atrial fibrillation in 2007 was significantly associated with a decrease in bisphosphonate use among patients with hip fracture.