Severe Hypocalcemia With Denosumab Among Older Female Dialysis-Dependent Patients.

Importance: Dialysis-dependent patients experience high rates of morbidity from fractures, yet little evidence is available on optimal treatment strategies. Chronic kidney disease-mineral and bone disorder is nearly universal in dialysis-dependent patients, complicating diagnosis and treatment of skeletal fragility. Objective: To examine the incidence and comparative risk of severe hypocalcemia with denosumab compared with oral bisphosphonates among dialysis-dependent patients treated for osteoporosis. Design, Setting, and Participants: Retrospective cohort study of female dialysis-dependent Medicare patients aged 65 years or older who initiated treatment with denosumab or oral bisphosphonates from 2013 to 2020. Clinical performance measures including monthly serum calcium were obtained through linkage to the Consolidated Renal Operations in a Web-Enabled Network database. Exposures: Denosumab, 60 mg, or oral bisphosphonates. Main Outcomes and Measures: Severe hypocalcemia was defined as total albumin-corrected serum calcium below 7.5 mg/dL (1.88 mmol/L) or a primary hospital or emergency department hypocalcemia diagnosis (emergent care). Very severe hypocalcemia (serum calcium below 6.5 mg/dL [1.63 mmol/L] or emergent care) was also assessed. Inverse probability of treatment-weighted cumulative incidence, weighted risk differences, and weighted risk ratios were calculated during the first 12 treatment weeks. Results: In the unweighted cohorts, 607 of 1523 denosumab-treated patients and 23 of 1281 oral bisphosphonate-treated patients developed severe hypocalcemia. The 12-week weighted cumulative incidence of severe hypocalcemia was 41.1% with denosumab vs 2.0% with oral bisphosphonates (weighted risk difference, 39.1% [95% CI, 36.3%-41.9%]; weighted risk ratio, 20.7 [95% CI, 13.2-41.2]). The 12-week weighted cumulative incidence of very severe hypocalcemia was also increased with denosumab (10.9%) vs oral bisphosphonates (0.4%) (weighted risk difference, 10.5% [95% CI, 8.8%-12.0%]; weighted risk ratio, 26.4 [95% CI, 9.7-449.5]). Conclusions and Relevance: Denosumab was associated with a markedly higher incidence of severe and very severe hypocalcemia in female dialysis-dependent patients aged 65 years or older compared with oral bisphosphonates. Given the complexity of diagnosing the underlying bone pathophysiology in dialysis-dependent patients, the high risk posed by denosumab in this population, and the complex strategies required to monitor and treat severe hypocalcemia, denosumab should be administered after careful patient selection and with plans for frequent monitoring.

Risk of fetal or neonatal death or neonatal intensive care unit admission associated with gadolinium magnetic resonance imaging exposure during pregnancy.

BACKGROUND: Concerns have been raised about prenatal exposure to magnetic resonance imaging with gadolinium-based contrast agents because of nonclinical findings of gadolinium retention in fetal tissue and 1 population-based study reporting an association with adverse pregnancy outcomes. OBJECTIVE: This study aimed to evaluate the association between prenatal magnetic resonance imaging exposure with and without gadolinium-based contrast agents and fetal and neonatal death and neonatal intensive care unit admission. STUDY DESIGN: We constructed a retrospective cohort of >11 million Medicaid-covered pregnancies between 1999 and 2014 to evaluate the association between prenatal magnetic resonance imaging exposure with and without gadolinium-based contrast agents and fetal and neonatal death (primary endpoint) and neonatal intensive care unit admissions (secondary endpoint). Medicaid claims data were linked to medical records, Florida birth and fetal death records, and the National Death Index to validate the outcomes and gestational age estimates. Pregnancies with multiples, concurrent cancer, teratogenic drug exposure, magnetic resonance imaging focused on fetal or pelvic evaluation, undetermined gadolinium-based contrast agent use, or those preceded by or contemporaneous with congenital anomaly diagnoses were excluded. We adjusted for potential confounders with standardized mortality ratio weighting using propensity scores. RESULTS: Among 5991 qualifying pregnancies, we found 11 fetal or neonatal deaths in the gadolinium-based contrast agent magnetic resonance imaging group (1.4%) and 73 in the non-gadolinium-based contrast agent magnetic resonance imaging group (1.4%) with an adjusted relative risk of 0.73 (95% confidence interval, 0.34-1.55); the neonatal intensive care unit admission adjusted relative risk was 1.03 (0.76-1.39). Sensitivity analyses investigating the timing of magnetic resonance imaging or repeat magnetic resonance imaging exposure during pregnancy and simulating the impact of exposure misclassification corroborated these results. CONCLUSION: This study addressed the safety concerns related to prenatal exposure to gadolinium-based contrast agents used in magnetic resonance imaging and the risk thereof on fetal and neonatal death or the need for neonatal intensive care unit admission. Although the results on fatal or severe acute effects are reassuring, the impact on subacute outcomes was not evaluated.

Utility of fertility procedures and prenatal tests to estimate gestational age for live-births and stillbirths in electronic health plan databases.

PURPOSE: Current algorithms to evaluate gestational age (GA) during pregnancy rely on hospital coding at delivery and are not applicable to non-live births. We developed an algorithm using fertility procedures and fertility tests, without relying on delivery coding, to develop a novel GA algorithm in live-births and stillbirths. METHODS: Three pregnancy cohorts were identified from 16 health-plans in the Sentinel System: 1) hospital admissions for live-birth, 2) hospital admissions for stillbirth, and 3) medical chart-confirmed stillbirths. Fertility procedures and prenatal tests, recommended within specific GA windows were evaluated for inclusion in our GA algorithm. Our GA algorithm was developed against a validated delivery-based GA algorithm in live-births, implemented within a sample of chart-confirmed stillbirths, and compared to national estimates of GA at stillbirth. RESULTS: Our algorithm, including fertility procedures and 11 prenatal tests, assigned a GA at delivery to 97.9% of live-births and 92.6% of stillbirths. For live-births (n = 4 701 207), it estimated GA within 2 weeks of a reference delivery-based GA algorithm in 82.5% of pregnancies, with a mean difference of 3.7 days. In chart-confirmed stillbirths (n = 49), it estimated GA within 2 weeks of the clinically recorded GA at delivery for 80% of pregnancies, with a mean difference of 11.1 days. Implementation of the algorithm in a cohort of stillbirths (n = 40 484) had an increased percentage of deliveries after 36 weeks compared to national estimates. CONCLUSIONS: In a population of primarily commercially-insured pregnant women, fertility procedures and prenatal tests can estimate GA with sufficient sensitivity and accuracy for utility in pregnancy studies.

Validation of an ICD-10-based algorithm to identify stillbirth in the Sentinel System.

PURPOSE: To develop and validate an International Classification of Diseases, 10th Revision, Clinical Modification (ICD-10-CM)-based algorithm to identify cases of stillbirth using electronic healthcare data. METHODS: We conducted a retrospective study using claims data from three Data Partners (healthcare systems and insurers) in the Sentinel Distributed Database. Algorithms were developed using ICD-10-CM diagnosis codes to identify potential stillbirths among females aged 12-55 years between July 2016 and June 2018. A random sample of medical charts (N = 169) was identified for chart abstraction and adjudication. Two physician adjudicators reviewed potential cases to determine whether a stillbirth event was definite/probable, the date of the event, and the gestational age at delivery. Positive predictive values (PPVs) were calculated for the algorithms. Among confirmed cases, agreement between the claims data and medical charts was determined for the outcome date and gestational age at stillbirth. RESULTS: Of the 110 potential cases identified, adjudicators determined that 54 were stillbirth events. Criteria for the algorithm with the highest PPV (82.5%; 95% CI, 70.9%-91.0%) included the presence of a diagnosis code indicating gestational age ≥20 weeks and occurrence of either >1 stillbirth-related code or no other pregnancy outcome code (i.e., livebirth, spontaneous abortion, induced abortion) recorded on the index date. We found ≥90% agreement within 7 days between the claims data and medical charts for both the outcome date and gestational age at stillbirth. CONCLUSIONS: Our results suggest that electronic healthcare data may be useful for signal detection of medical product exposures potentially associated with stillbirth.

Misclassification in Assessment of First Trimester In-utero Exposure to Drugs Used Proximally to Conception: the Example of Letrozole Utilization for Infertility Treatment.

Letrozole is an aromatase inhibitor that has an unapproved use for ovulation induction with infertility. Because of the proximity of this use to conception, we selected letrozole to study the effect of 3 different methods for identifying the pregnancy start date and their impact on exposure misclassification. Using electronic health data from the US Sentinel database (2001-2015), we identified live-birth pregnancies conceived through in-vitro fertilization or intrauterine insemination. The pregnancy start was calculated using 1) a validated algorithm to estimate the last menstrual period (LMP), 2) LMP + 14 days (i.e., conception estimate), and 3) the fertility-procedure date. We identified 47,628 live-births after intrauterine insemination (n = 24,962) and in-vitro fertilization (n = 22,666), in which 2,458 (5.3%) mothers received letrozole. The algorithm-based conception estimate occurred within 14 days of the fertility procedure for 78.3% of pregnancies. Defining pregnancy start as LMP (45.7/1,000 pregnancies) or LMP + 14 days (12.7/1,000 pregnancies) overestimated letrozole exposure during pregnancy by 8.4-fold and 2.3-fold, respectively, compared with defining it at the date of the fertility procedure (5.5/1,000 pregnancies). While most studies of drug utilization in pregnancy use LMP as the conventional pregnancy start, this introduced substantial exposure misclassification in the example of letrozole. LMP + 14 days was less biased. Researchers should carefully consider the impact of the method for identifying the pregnancy start date on the potential for exposure misclassification.

First-Trimester Exposure to Gadolinium-based Contrast Agents: A Utilization Study of 4.6 Million U.S. Pregnancies.

BackgroundThe safety of gadolinium-based contrast agent (GBCA) exposure during pregnancy has not been established, and the use of GBCAs during pregnancy is not recommended unless it is essential to the health of the woman or fetus.PurposeTo examine the prevalence of GBCA exposure in a large sample of pregnancies resulting in a live birth.Materials and MethodsThe Sentinel Distributed Database was used to retrospectively identify U.S. pregnancies that resulted in live births between 2006 and 2017 from 16 data partners. The main outcome was the prevalence of MRI procedures with and without GBCAs, sorted by anatomic location and trimester, among pregnant and matched comparator women.ResultsAmong 4 692 744 pregnancies resulting in a live birth, we identified 6879 exposures to GBCAs in 5457 pregnancies, representing one contrast-enhanced MRI examination per 860 pregnancies (0.12% of all pregnancies). Most contrast-enhanced MRI examinations were performed in the head (n = 3499), although pelvic and abdominal MRI constituted 22.3% (n = 1536) of all contrast-enhanced MRI examinations during pregnancy. The majority (70.2%) of GBCA exposures occurred during the first trimester, with a 4.3-fold greater prevalence compared with that in the second trimester and a 5.1-fold greater prevalence compared with that in the third trimester.ConclusionThis study identified higher rates of gadolinium-based contrast agent (GBCA) exposure during the first few weeks of pregnancy compared with the later weeks of pregnancy, suggesting inadvertent exposure to GBCAs might occur before pregnancy is recognized.© RSNA, 2019Online supplemental material is available for this article.See also the editorial by Kallmes and Watson in this issue.

Utilization of drugs with pregnancy exposure registries during pregnancy.

PURPOSE: To describe the utilization of drugs with pregnancy exposure registries by trimester during pregnancy, in comparison with matched nonpregnant episodes and a pre-pregnancy period. METHODS: We identified live-born deliveries from women aged 10 to 54 years and matched the pregnancies 1:1 with nonpregnant episodes from a comparator cohort not delivering live-born infants, using data from 2001 to 2013 in the Sentinel Distributed Database. We evaluated the utilization of 34 drugs with pregnancy exposure registries, comparing utilization during pregnancy to the matched nonpregnant episodes, and to the 90 days before pregnancy. RESULTS: We identified 1 895 597 pregnancies ending in live births in 1 598 697 women and 1 895 597 matched nonpregnant episodes in 1 582 581 women. We observed a lower prevalence of use for most drugs during pregnancy compared with the matched nonpregnant episodes, and the 90-day pre-pregnancy period. The median (interquartile range) prevalence ratio of use, at any time during pregnancy, for all products was 0.2 (0.1-0.3) comparing pregnant to nonpregnant episodes. Overall, there was a decrease in drug utilization by trimester; from 2.6% in the 90 days preceding pregnancy to 2.1% in the first trimester, 1.1% in the second trimester, and 0.9% in the third trimester. CONCLUSIONS: Among drugs with pregnancy exposure registries, use was less during pregnancy compared with before pregnancy and to the matched nonpregnant episodes. The lower utilization during pregnancy suggests that women may be avoiding these drugs to minimize potentially harmful exposure during pregnancy. This lower utilization may increase the challenges of further studying the safety of these drugs using pregnancy exposure registries.

A systematic review of pregnancy exposure registries: examination of protocol-specified pregnancy outcomes, target sample size, and comparator selection.

PURPOSE: Our study sought to systematically evaluate protocol-specified study methodology in prospective pregnancy exposure registries including pre-specified pregnancy outcomes, power calculations for sample size, and comparator group selection. METHODS: U.S. pregnancy exposure registries designed to evaluate safety of drugs or biologics were identified from www.clinicaltrials.gov, the FDA's Office of Women's Health website, and the FDA's list of postmarketing studies. Protocols or similar documentation were obtained. RESULTS: We identified 35 U.S. registries for drugs or biologic use during pregnancy. All registries assessed risk for overall major congenital malformations. Pre-specified target enrollment was stated for 18 (51%) registries, and ranged from 150 to 500 exposed pregnancies (median 300). Thirty-two (91%) registries identified at least one comparison group, but only nine (26%) planned to use an internal comparator. The most common external comparator group (n = 24, 69%) was the Metropolitan Atlanta Congenital Defects Program (MACDP). CONCLUSIONS: No registries were designed to have sufficient power to assess specific malformations, despite the plausibility that most teratogens cause specific defects. Only half of the registries included a power analysis. Despite their common use, external comparators, including MACDP, have important limitations. In the absence of randomized controlled trial data in pregnant women, pregnancy registries remain an important tool as part of a comprehensive pregnancy surveillance program; however, pregnancy registries alone may not be sufficient to obtain adequate data regarding risks of specific malformations. Published 2016. This article is a U.S. Government work and is in the public domain in the USA.

Antiemetic use among pregnant women in the United States: the escalating use of ondansetron.

PURPOSE: To examine ondansetron use in pregnancy in the context of other antiemetic use among a large insured United States population of women delivering live births. METHODS: We assessed ondansetron and other antiemetic use among pregnant women delivering live births between 2001 and 2015 in 15 data partners contributing data to the Mini-Sentinel Distributed Database. We identified live birth pregnancies using a validated algorithm, and all forms of ondansetron and other available antiemetics were identified using National Drug Codes or procedure codes. We assessed the prevalence of antiemetic use by trimester, calendar year, and formulation. RESULTS: In over 2.3 million pregnancies, the prevalence of ondansetron, promethazine, metoclopramide, or doxylamine/pyridoxine use anytime in pregnancy was 15.2, 10.3, 4.0, and 0.4%, respectively. Ondansetron use increased from <1% of pregnancies in 2001 to 22.2% in 2014, with much of the increase attributable to oral ondansetron beginning in 2006. Promethazine and metoclopramide use increased modestly between 2001 (13.8%, 3.2%) and 2006 (16.0%, 6.0%) but decreased annually through 2014 (8.0%, 3.2%). Doxylamine/pyridoxine, approved for management of nausea and vomiting in pregnancy in 2013, was used in 1.8% of pregnancies in 2014. For all antiemetics, use was highest in the first trimester. CONCLUSIONS: We observed a marked increase in ondansetron use by study year, prescribed to nearly one-quarter of insured pregnant women in 2014, occurring in conjunction with decreased use of promethazine and metoclopramide. Given the widespread use of ondansetron in pregnancy, data establishing product efficacy and methodologically rigorous evaluation of post-marketing safety are needed. Published 2017. This article is a U.S. Government work and is in the public domain in the USA.

Male breast cancer and 5α-reductase inhibitors finasteride and dutasteride.

PURPOSE: We examined the association between 5α-reductase inhibitors and male breast cancer. MATERIALS AND METHODS: Study participants were men 40 to 85 years old, with prescription and medical coverage, enrolled in the United States IMS LifeLink™ Health Plan claims database between 2001 and 2009. Cases required a primary breast cancer diagnosis (ICD-9-CM 175.x) on 2 different dates and a procedural code for mastectomy or lumpectomy/partial mastectomy with evidence of continuous care (radiation/chemotherapy or diagnoses in 2 or more months). Eligible controls were within 5 years in age and had duration of prior health care enrollment within 6 weeks. Risk set sampling selected 20 controls per case. We assessed the rate ratio for male breast cancer with 5α-reductase inhibitor exposure using conditional logistic regression. Analyses were stratified by duration of health care enrollment before diagnosis (1 year or more, 2 years or more and 3 years or more), each incremental 180 and 365 days of cumulative 5α-reductase inhibitor exposure, and period specific time frames before diagnosis (years 1, 2 and 3). RESULTS: We identified 339 breast cancer cases matched to 6,780 controls. No statistically significant associations were observed between 5α-reductase inhibitors and breast cancer regardless of exposure assessment before the index date (1 year or more-RR 0.70, 95% CI 0.34-1.45; 2 years or more-RR 0.59, 95% CI 0.24-1.48; or 3 years or more-RR 0.75, 95% CI 0.27-2.10). Each subsequent 180 days (RR 1.02, 95% CI 0.67-1.53) and 365 days (RR 1.03, 95% CI 0.45-2.37) of cumulative 5α-reductase inhibitor therapy and period specific rate ratios also showed null associations. CONCLUSIONS: The lack of an association in our study suggests that the development of breast cancer should not influence the prescribing of 5α-reductase inhibitor therapy.

Risk of venous thromboembolism in women with polycystic ovary syndrome: a population-based matched cohort analysis.

BACKGROUND: There is an increased risk of venous thromboembolism among women taking oral contraceptives. However, whether there is an additional risk among women with polycystic ovary syndrome (PCOS) is unknown. METHODS: We developed a population-based cohort from the IMS LifeLink Health Plan Claims Database, which includes managed care organizations in the United States. Women aged 18-46 years taking combined oral contraceptives and who had a claim for PCOS (n = 43 506) were matched, based on a propensity score, to control women (n = 43 506) taking oral contraceptives. Venous thromboembolism was defined using administrative coding and use of anticoagulation. We used Cox proportional hazards models to assess the relative risk (RR) of venous thromboembolism among users of combined oral contraceptives with and without PCOS. RESULTS: The incidence of venous thromboembolism among women with PCOS was 23.7/10 000 person-years, while that for matched controls was 10.9/10 000 person-years. Women with PCOS taking combined oral contraceptives had an RR for venous thromboembolism of 2.14 (95% confidence interval [CI] 1.41-3.24) compared with other contraceptive users. The incidence of venous thromboembolism was 6.3/10 000 person-years among women with PCOS not taking oral contraceptives; the incidence was 4.1/10 000 person-years among matched controls. The RR of venous thromboembolism among women with PCOS not taking oral contraceptives was 1.55 (95% CI 1.10-2.19). INTERPRETATION: We found a 2-fold increased risk of venous thromboembolism among women with PCOS who were taking combined oral contraceptives and a 1.5-fold increased risk among women with PCOS not taking oral contraceptives. Physicians should consider the increased risk of venous thromboembolism when prescribing contraceptive therapy to women with PCOS.

Risk of acute kidney injury associated with the use of fluoroquinolones.

BACKGROUND: Case reports indicate that the use of fluoroquinolones may lead to acute kidney injury. We studied the association between the use of oral fluoroquinolones and acute kidney injury, and we examined interaction with renin-angiotensin-system blockers. METHODS: We formed a nested cohort of men aged 40-85 enrolled in the United States IMS LifeLink Health Plan Claims Database between 2001 and 2011. We defined cases as men admitted to hospital for acute kidney injury, and controls were admitted to hospital with a different presenting diagnosis. Using risk-set sampling, we matched 10 controls to each case based on hospital admission, calendar time (within 6 wk), cohort entrance (within 6 wk) and age (within 5 yr). We used conditional logistic regression to assess the rate ratio (RR) for acute kidney injury with current, recent and past use of fluoroquinolones, adjusted by potential confounding variables. We repeated this analysis with amoxicillin and azithromycin as controls. We used a case-time-control design for our secondary analysis. RESULTS: We identified 1292 cases and 12 651 matched controls. Current fluoroquinolone use had a 2.18-fold (95% confidence interval [CI] 1.74-2.73) higher adjusted RR of acute kidney injury compared with no use. There was no association between acute kidney injury and recent (adjusted RR 0.87, 95% CI 0.66-1.16) or past (RR 0.86, 95% CI 0.66-1.12) use. The absolute increase in acute kidney injury was 6.5 events per 10 000 person-years. We observed 1 additional case per 1529 patients given fluoroquinolones or per 3287 prescriptions dispensed. The dual use of fluoroquinolones and renin-angiotensin-system blockers had an RR of 4.46 (95% CI 2.84-6.99) for acute kidney injury. Our case-time-control analysis confirmed an increased risk of acute kidney injury with fluoroquinolone use (RR 2.16, 95% CI 1.52-3.18). The use of amoxicillin or azithromycin was not associated with acute kidney injury. INTERPRETATION: We found a small, but significant, increased risk of acute kidney injury among men with the use of oral fluoroquinolones, as well as a significant interaction between the concomitant use of fluoroquinolones and renin-angiotensin-system blockers.

Polycystic ovary syndrome and combined oral contraceptive use: a comparison of clinical practice in the United States to treatment guidelines.

The October 2010 ESHRE/ASRM polycystic ovary syndrome (PCOS) workshop concluded: (1) all combined oral contraceptives (COC) appear to have equal efficacy for PCOS, (2) addition of antiandrogens (spironolactone) to COCs has little treatment benefit and (3) metformin does not improve the live-birth rate and should only be used with impaired glucose tolerance. We compared these guidelines to current practice in the United States IMS claims-database. Time-series analyses were conducted by calendar-year in women with PCOS to evaluate prescribing preferences for COCs, concomitant use of spironolactone, and utilization of metformin. Trends were analyzed with linear regression. Our cohort included 1.6 million women taking COCs, 46 780 with a PCOS claim. Drospirenone utilization increased by 1.52% (SE:0.48%, p = 0.007) per-year more in women with PCOS (4.16%, SE:0.45%, p < 0.001) than in women without PCOS (2.64%, SE:0.17%, p < 0.001)). Concomitant use of drospirenone and spironolactone was common (14.26%) and increased by 0.75% (SE:0.15%, p = 0.002) per-year. Although plasma glucose tests were unavailable, women with PCOS were more likely to take metformin than have a diabetes claim (45.8% versus 15.2%, p < 0.001), indicating some women likely receive metformin solely for PCOS. Our data suggests further attention is needed to medication management of PCOS to bridge the gap between guidelines and practice.

Validation of an ICD-9-Based Algorithm to Identify Stillbirth Episodes from Medicaid Claims Data.

INTRODUCTION: In administrative data, accurate timing of exposure relative to gestation is critical for determining the effect of potential teratogen exposure on pregnancy outcomes. OBJECTIVE: To develop an algorithm for identifying stillbirth episodes in the ICD-9-CM era using national Medicaid claims data (1999-2014). METHODS: Unique stillbirth episodes were identified from clusters of medical claims using a hierarchy that identified the encounter with the highest potential of including the actual stillbirth delivery and that delineated subsequent pregnancy episodes. Each episode was validated using clinical detail on retrieved medical records as the gold standard. RESULTS: Among 220 retrieved records, 197 were usable for validation of 1417 stillbirth episodes identified by the algorithm. The positive predictive value (PPV) was 64.0% (57.3-70.7%) overall, 80.4% (73.8-87.1%) for inpatient episodes, 28.2% (14.1-42.3%) for outpatient-only episodes, and 20.0% (2.5-37.5%) for outpatient episodes with overlapping hospitalizations. The absolute difference between the dates of the algorithm-specified stillbirth delivery and the medical record-based event was 4.2 ± 24.3 days overall, 1.7 ± 7.7 days for inpatient episodes, 14.3 ± 51.4 days for outpatient-only episodes, and 1.0 ± 2.0 days for outpatient episodes that overlapped with a hospitalization. Excluding all outpatient episodes, as well as pregnancies involving multiple births, the PPV increased to 82.7% (76.8-89.8%). CONCLUSIONS: Our algorithm to identify stillbirths from administrative claims data had a moderately high PPV. Positive predictive value was substantially increased by restricting the setting to inpatient episodes and using only input diagnostic codes for singleton stillbirths.

Oral fluoroquinolones and the risk of retinal detachment.

CONTEXT: Fluoroquinolones are commonly prescribed classes of antibiotics. Despite numerous case reports of ocular toxicity, a pharmacoepidemiological study of their ocular safety, particularly retinal detachment, has not been performed. OBJECTIVE: To examine the association between use of oral fluoroquinolones and the risk of developing a retinal detachment. DESIGN, SETTING, AND PATIENTS: Nested case-control study of a cohort of patients in British Columbia, Canada, who had visited an ophthalmologist between January 2000 and December 2007. Retinal detachment cases were defined as a procedure code for retinal repair surgery within 14 days of a physician service code. Ten controls were selected for each case using risk-set sampling, matching on age and the month and year of cohort entry. MAIN OUTCOME MEASURE: The association between retinal detachment and current, recent, or past use of an oral fluoroquinolone. RESULTS: From a cohort of 989,591 patients, 4384 cases of retinal detachment and 43,840 controls were identified. Current use of fluoroquinolones was associated with a higher risk of developing a retinal detachment (3.3% of cases vs 0.6% of controls; adjusted rate ratio [ARR], 4.50 [95% CI, 3.56-5.70]). Neither recent use (0.3% of cases vs 0.2% of controls; ARR, 0.92 [95% CI, 0.45-1.87]) nor past use (6.6% of cases vs 6.1% of controls; ARR, 1.03 [95% CI, 0.89-1.19]) was associated with a retinal detachment. The absolute increase in the risk of a retinal detachment was 4 per 10,000 person-years (number needed to harm = 2500 computed for any use of fluoroquinolones). There was no evidence of an association between development of a retinal detachment and ß-lactam antibiotics (ARR, 0.74 [95% CI, 0.35-1.57]) or short-acting ß-agonists (ARR, 0.95 [95% CI, 0.68-1.33]). CONCLUSION: Patients taking oral fluoroquinolones were at a higher risk of developing a retinal detachment compared with nonusers, although the absolute risk for this condition was small.

The association between drospirenone and hyperkalemia: a comparative-safety study.

BACKGROUND: Drospirenone/ethinyl-estradiol is an oral contraceptive (OC) that possesses unique antimineralocorticoid activity. It is conjectured that drospirenone, taken alone or concomitantly with spironolactone, may be associated with an increased risk of hyperkalemia. METHODS: A retrospective cohort study was conducted evaluating women between 18-46 years of age in the Lifelink™ Health Plan Claims Database. The study was restricted to new users of OCs between 1997-2009. Cox proportional hazards models were used to estimate the time to first occurrence of hyperkalemia diagnosis. The main analysis compared OCs containing drospirenone with OCs containing levonorgestrel, a second generation OC not known to impact potassium homeostasis. Logistic regression evaluated concomitant prescribing of drospirenone and spironolactone RESULTS: The cohort included 1,148,183 women, averaging 28.8 years of age and 280 days of OC therapy. 2325 cases of hyperkalemia were identified. The adjusted hazard ratio (HR) for hyperkalemia with drospirenone compared to levonorgestrel was 1.10 (95%CI 0.95-1.26). There was an increased risk of hyperkalemia with norethindrone HR 1.15 (95%CI: 1.00-1.33) and norgestimate HR 1.27 (95%CI: 1.11-1.46). Other OCs were unassociated with hyperkalemia. The odds of receiving spironolactone while taking drospirenone were 2.66 (95%CI 2.53-2.80) times higher than the odds of receiving spironolactone and levonorgestrel. Only 6.5% of patients taking drospirenone and spironolactone had a serum potassium assay within 180 days of starting concomitant therapy. CONCLUSIONS: A clinically significant signal for hyperkalemia with drospirenone was not demonstrated in the current study. Despite the bolded warning for hyperkalemia with joint drospirenone and spironolactone administration, physicians are actually using them together preferentially, and are not following the recommended potassium monitoring requirements in the package insert.

Idelalisib for Treatment of Relapsed Follicular Lymphoma and Chronic Lymphocytic Leukemia: A Comparison of Treatment Outcomes in Clinical Trial Participants vs Medicare Beneficiaries.

Importance: Idelalisib (IDEL) is approved as monotherapy in relapsed follicular lymphoma (FL) and with rituximab (IDEL+R) for relapsed chronic lymphocytic leukemia (CLL). Toxic effects can be severe and treatment-limiting. Outcomes in a real-world population are not yet characterized. Objective: We compared IDEL treatment outcomes in the clinical setting with outcomes in clinical trial data. Design, Setting, and Participants: This cohort study compared clinical trial participants treated with IDEL, aged 65 years or older, in studies 101-09 and 312-0116 with Medicare beneficiaries treated with IDEL of the same disease state and treatment regimen. Study 101-09 was a phase 2, single-group, open-label trial supporting accelerated approval of IDEL for relapsed or refractory FL. Study 312-0116 was a phase 3, multicenter, randomized, double-blind trial supporting approval of IDEL+R for relapsed CLL. Analyses were conducted between February and December 2018. Main Outcomes and Measures: Treatment duration, on-treatment and overall mortality, and serious and fatal infections were compared between trial participants and Medicare beneficiaries. Cox proportional hazards models quantified differences by cohort. Results: We identified 26 trial participants (mean [SD] age, 73 [4.9] years; 12 [46.2%] women) and 305 Medicare beneficiaries (mean [SD] age, 76 [6.9] years; 103 [54.8%] women) receiving IDEL for FL and 89 trial participants (mean [SD] age, 74 [6.0] years; 30 [33.7%] women) and 294 Medicare beneficiaries (mean age, 76 [6.3] years; 111 [37.8%] women) receiving IDEL+R for CLL. Medicare beneficiaries were older with higher comorbidity; had a shorter median treatment duration for CLL (173 days vs 473 days, P < .001) but not FL (114, days vs 160 days, P = .38); a numerically higher mortality rate (CLL: HR, 1.40; 95% CI, 0.93-2.11; FL: HR, 1.39; 95% CI, 0.69-2.78); and a significantly higher fatal infection rate per 100 person-years for CLL (18.4 vs 9.8, P = .04) and a numerically higher rate for FL (27.6 vs 18.6, P = .54), compared with trial participants. Trial participants had approximately twice as many dose reductions (CLL: 32.6% vs 18.0%; P = .003; FL: 38.5% vs 16.1%; P = .02). Among Medicare beneficiaries, a hospitalized infection within 6 months prior to IDEL initiation was associated with a 2.11-fold increased risk for on-treatment fatal infections (95% CI, 1.44-3.10). Despite a March 2016 recommendation for Pneumocystis jirovecii pneumonia prophylaxis in patients treated with IDEL, prophylaxis rates were low after March 2016 (FL: 25%, CLL: 37%). Conclusions and Relevance: We observed substantial imbalances in baseline comorbidities and treatment outcomes between Medicare beneficiaries and trial participants aged 65 years or older. Immunosuppression-related toxic effects, including infections, may have been somewhat reduced in trials by more frequent dose reductions and exclusion of patients with ongoing infections. Selective eligibility criteria and closer monitoring of trial patients may be responsible for limited generalizability of trial data to clinical practice.

Healthy User Bias in Comparative Safety Studies for Brand-Name vs. Generic Products: The Example of Warfarin.

Warfarin was selected as a case study to examine confounding when comparing a product across different manufacturers because it is a narrow therapeutic index drug with prevalent beliefs for brand-name superiority. Medicare beneficiaries aged ≥65 years with atrial fibrillation and an incident outpatient warfarin prescription from July 2006 through July 2015 were included in the study population (N = 746,098). Substantial imbalances were observed between brand-name warfarin and generics for (i) clinical comorbidity, (ii) socioeconomic status, (iii) prescriber specialty, (iv) recent ambulatory and emergent care, (v) drug adherence, (vi) pharmacy setting (e.g., retail, mail-order), and (vii) risk scores for bleeding and thrombosis. Patients receiving brand-name warfarin were healthier than patients receiving generic manufactured warfarin. Utilization of generic warfarin products also differed by geographic region and pharmacy setting. Manufacturer-level comparative-safety studies for causal inference should carefully consider the presence of these imbalances and their potential for introducing healthy user bias.

Effects of deferasirox dose and decreasing serum ferritin concentrations on kidney function in paediatric patients: an analysis of clinical laboratory data from pooled clinical studies.

BACKGROUND: Serious and fatal deferasirox-induced kidney injury has been reported in paediatric patients. This study aimed to investigate the effects of deferasirox dose and serum ferritin concentrations on kidney function and the effect of impaired kidney function on dose-normalised deferasirox minimum plasma concentration (Cmin). METHODS: We did a case-control analysis using pooled data from ten clinical studies. We identified transfusion-dependent patients with thalassaemia, aged 2-15 years, who were receiving deferasirox and had available baseline and follow-up serum creatinine and ferritin measurements. Cases of acute kidney injury (AKI) were defined according to an estimated glomerular filtration rate (eGFR) threshold of 90 mL/min per 1·73 m2 or less (if baseline eGFR was ≥100 mL/min per 1·73 m2), an eGFR of 60 mL/min per 1·73 m2 or less (if baseline eGFR was <100 mL/min per 1·73 m2), or an eGFR decrease from baseline of at least 25%. Cases were matched to control visits (eGFR ≥120 mL/min per 1·73 m2) on age, sex, study site, and time since drug initiation. We calculated rate ratios for AKI using conditional logistic regression, and evaluated the effect of eGFR changes on Cmin. FINDINGS: Among 1213 deferasirox-treated paediatric patients, 162 cases of AKI and 621 matched control visits were identified. Patients with AKI had a mean 50·2% (SD 15·5) decrease in eGFR from baseline, compared with a 6·9% (29·8) decrease in controls. A significantly increased risk for AKI (rate ratio 1·26, 95% CI 1·08-1·48, p=0·00418) was observed per 5 mg/kg per day increase in deferasirox dispersible tablet dose (equivalent to a 3·5 mg/kg per day dose of film-coated tablets or granules), above the typical starting dose (20 mg/kg per day). An increased risk (1·25, 1·01-1·56, p=0·0400) for AKI was also observed per 250 µg/L decrease in serum ferritin, starting from 1250 µg/L. High-dose deferasirox (dispersible tablet dose >30 mg/kg per day) resulted in an increased risk (4·47, 1·25-15·95, p=0·0209) for AKI when serum ferritin was less than 1000 µg/L. Decreases in eGFR were associated with increased Cmin. INTERPRETATION: Deferasirox can cause AKI in a dose-dependent manner. The increased AKI risk with high-dose deferasirox and lower serum ferritin concentration is consistent with overchelation as a causative factor. Small decreases in eGFR correlate with increased deferasirox Cmin, especially in younger patients. Physicians should closely monitor renal function and serum ferritin, use the lowest effective dose to maintain acceptable body iron burden, and interrupt deferasirox treatment when AKI or volume depletion are suspected. FUNDING: None.