Assessing Heterogeneity of Treatment Effect in Real-World Data.

Increasing availability of real-world data (RWD) generated from patient care enables the generation of evidence to inform clinical decisions for subpopulations of patients and perhaps even individuals. There is growing opportunity to identify important heterogeneity of treatment effects (HTE) in these subgroups. Thus, HTE is relevant to all with interest in patients' responses to interventions, including regulators who must make decisions about products when signals of harms arise postapproval and payers who make coverage decisions based on expected net benefit to their beneficiaries. Prior work discussed HTE in randomized studies. Here, we address methodological considerations when investigating HTE in observational studies. We propose 4 primary goals of HTE analyses and the corresponding approaches in the context of RWD: to confirm subgroup effects, to describe the magnitude of HTE, to discover clinically important subgroups, and to predict individual effects. We discuss other possible goals including exploring prognostic score- and propensity score-based treatment effects, and testing the transportability of trial results to populations different from trial participants. Finally, we outline methodological needs for enhancing real-world HTE analysis.

Ototoxicity After Cisplatin-Based Chemotherapy: Factors Associated With Discrepancies Between Patient-Reported Outcomes and Audiometric Assessments.

OBJECTIVES: To provide new information on factors associated with discrepancies between patient-reported and audiometrically defined hearing loss (HL) in adult-onset cancer survivors after cisplatin-based chemotherapy (CBCT) and to comprehensively investigate risk factors associated with audiometrically defined HL. DESIGN: A total of 1410 testicular cancer survivors (TCS) ≥6 months post-CBCT underwent comprehensive audiometric assessments (0.25 to 12 kHz) and completed questionnaires. HL severity was defined using American Speech-Language-Hearing Association criteria. Multivariable multinomial regression identified factors associated with discrepancies between patient-reported and audiometrically defined HL and multivariable ordinal regression evaluated factors associated with the latter. RESULTS: Overall, 34.8% of TCS self-reported HL. Among TCS without tinnitus, those with audiometrically defined HL at only extended high frequencies (EHFs) (10 to 12 kHz) (17.8%) or at both EHFs and standard frequencies (0.25 to 8 kHz) (23.4%) were significantly more likely to self-report HL than those with no audiometrically defined HL (8.1%) [odds ratio (OR) = 2.48; 95% confidence interval (CI), 1.31 to 4.68; and OR = 3.49; 95% CI, 1.89 to 6.44, respectively]. Older age (OR = 1.09; 95% CI, 1.07 to 1.11, p < 0.0001), absence of prior noise exposure (OR = 1.40; 95% CI, 1.06 to 1.84, p = 0.02), mixed/conductive HL (OR = 2.01; 95% CI, 1.34 to 3.02, p = 0.0007), no hearing aid use (OR = 5.64; 95% CI, 1.84 to 17.32, p = 0.003), and lower education (OR = 2.12; 95% CI, 1.23 to 3.67, p = 0.007 for high school or less education versus postgraduate education) were associated with greater underestimation of audiometrically defined HL severity, while tinnitus was associated with greater overestimation (OR = 4.65; 95% CI, 2.64 to 8.20 for a little tinnitus, OR = 5.87; 95% CI, 2.65 to 13.04 for quite a bit tinnitus, and OR = 10.57; 95% CI, 4.91 to 22.79 for very much tinnitus p < 0.0001). Older age (OR = 1.13; 95% CI, 1.12 to 1.15, p < 0.0001), cumulative cisplatin dose (>300 mg/m2, OR = 1.47; 95% CI, 1.21 to 1.80, p = 0.0001), and hypertension (OR = 1.80; 95% CI, 1.28 to 2.52, p = 0.0007) were associated with greater American Speech-Language-Hearing Association-defined HL severity, whereas postgraduate education (OR = 0.58; 95% CI, 0.40 to 0.85, p = 0.005) was associated with less severe HL. CONCLUSIONS: Discrepancies between patient-reported and audiometrically defined HL after CBCT are due to several factors. For survivors who self-report HL but have normal audiometric findings at standard frequencies, referral to an audiologist for additional testing and inclusion of EHFs in audiometric assessments should be considered.

Healthcare utilization differences between an apixaban-based and warfarin-based strategy for acute venous thromboembolism in patients with end-stage kidney disease.

INTRODUCTION: Evidence suggests that an apixaban-based strategy to treat acute venous thromboembolism (VTE) in patients with End-Stage Kidney Disease (ESKD) may be safer than a warfarin-based strategy. Apixaban has an additional advantage of not requiring bridging with heparin which often necessitates long hospitalizations for patients with ESKD. We sought to determine if an apixaban-based strategy is associated with less healthcare utilization than a warfarin-based strategy. MATERIAL AND METHODS: We employed a new-user, active-comparator retrospective cohort study using inverse probability of treatment weights (IPTW) to adjust for confounding demographic and clinical variables. Patients with ESKD newly initiated on either apixaban or warfarin for an acute VTE between 2014 and 2018 in the United States Renal Data System were included. Outcomes were presence of index hospitalization, length of index hospitalization, total hospital days, total hospital days excluding index hospitalization, total emergency department (ED) visits that did not result in hospitalization, and total skilled nursing facility days. RESULTS: At six months, patients who received apixaban were less likely to have an index hospitalization, had a shorter index hospitalization (median of 4.0 vs 8.0 days, p < 0.001), and had fewer total hospital days. The IPTW and index year-adjusted incidence rate ratios of total hospital days at one, three, and six months were 0.83 (95 % confidence intervals (CI) 0.79-0.86), 0.84 (95 % CI 0.81-0.88), and 0.88 (95 % CI 0.83-0.92) for apixaban compared to warfarin. CONCLUSION: Among patients with ESKD and VTE, resource utilization for an apixaban-based strategy appears to be lower than for a warfarin-based strategy.

Associations of Nutritional, Environmental, and Metabolic Biomarkers with Diabetes-Related Mortality in U.S. Adults: The Third National Health and Nutrition Examination Surveys between 1988-1994 and 2016.

Background: Nutritional, environmental, and metabolic status may play a role in affecting the progression and prognosis of type 2 diabetes. However, results in identifying prognostic biomarkers among diabetic patients have been inconsistent and inconclusive. We aimed to evaluate the associations of nutritional, environmental, and metabolic status with disease progression and prognosis among diabetic patients. Methods: In a nationally representative sample in the NHANES III (The Third National Health and Nutrition Examination Survey, 1988−1994), we analyzed available data on 44 biomarkers among 2113 diabetic patients aged 20 to 90 years (mean age: 58.2 years) with mortality data followed up through 2016. A panel of 44 biomarkers from blood and urine specimens available from NHANES III were included in this study and the main outcomes as well as the measures are mortalities from all-causes. We performed weighted logistic regression analyses after controlling potential confounders. To assess incremental prognostic values of promising biomarkers beyond traditional risk factors, we compared c-statistics of the adjusted models with and without biomarkers, separately. Results: In total, 1387 (65.2%) deaths were documented between 1988 and 2016. We observed an increased risk of all-cause mortality associated with higher levels of serum C-reactive protein (p for trend = 0.0004), thyroid stimulating hormone (p for trend = 0.04), lactate dehydrogenase (p for trend = 0.02), gamma glutamyl transferase (p for trend = 0.02), and plasma fibrinogen (p for trend = 0.03), and urine albumin (p for trend < 0.0001). In contrast, higher levels of serum sodium (p for trend = 0.005), alpha carotene (p for trend = 0.006), and albumin (p for trend = 0.005) were associated with a decreased risk of all-cause mortality. In addition, these significant associations were not modified by age, sex, or race. Inclusion of thyroid stimulating hormone (p = 0.03), fibrinogen (p = 0.01), and urine albumin (p < 0.0001), separately, modestly improved the discriminatory ability for predicting all-cause mortality among diabetic patients. Conclusions: Our nationwide study findings provide strong evidence that some nutritional, environmental, and metabolic biomarkers were significant predictors of all-cause mortality among diabetic patients and may have potential clinical value for improving stratification of mortality risk.

Comparative Effectiveness and Safety of Direct Oral Anticoagulants Versus Warfarin Among Adults With Cancer and Atrial Fibrillation.

BACKGROUND: While clinical guidelines recommend direct-acting oral anticoagulants (DOAC) over warfarin to treat isolated nonvalvular atrial fibrillation, guidelines are silent regarding nonvalvular atrial fibrillation treatment among individuals with cancer, reflecting the paucity of evidence in this setting. We quantified relative risk of ischemic stroke or systemic embolism and major bleeding (primary outcomes), and all-cause and cardiovascular death (secondary outcomes) among older individuals with cancer and nonvalvular atrial fibrillation comparing DOACs and warfarin. METHODS: This retrospective cohort study used Surveillance, Epidemiology, and End Results cancer registry and linked US Medicare data from 2010 through 2016, and included individuals diagnosed with cancer and nonvalvular atrial fibrillation who newly initiated DOAC or warfarin. We used inverse probability of treatment weighting to control confounding. We used competing risk regression for primary outcomes and cardiovascular death, and Cox proportional hazard regression for all-cause death. RESULTS: Among 7675 individuals included in the cohort, 4244 (55.3%) received DOACs and 3431 (44.7%) warfarin. In the inverse probability of treatment weighting analysis, there was no statistically significant difference among DOAC and warfarin users in the risk of ischemic stroke or systemic embolism (1.24 versus 1.19 events per 100 person-years, adjusted hazard ratio 1.41 [95% CI, 0.92-2.14]), major bleeding (3.08 versus 4.49 events per 100 person-years, adjusted hazard ratio 0.90 [95% CI, 0.70-1.17]), and cardiovascular death (1.88 versus 3.14 per 100 person-years, adjusted hazard ratio 0.82 [95% CI, 0.59-0.1.13]). DOAC users had significantly lower risk of all-cause death (7.09 versus 13.3 per 100 person-years, adjusted hazard ratio 0.81 [95% CI, 0.69-0.94]) compared to warfarin users. CONCLUSIONS: Older adults with cancer and atrial fibrillation exposed to DOACs had similar risks of stroke and systemic embolism and major bleeding as those exposed to warfarin. Relative to warfarin, DOAC use was associated with a similar risk of cardiovascular death and a lower risk of all-cause death.

Use of oral anticoagulants among individuals with cancer and atrial fibrillation in the United States, 2010-2016.

BACKGROUND: Anticoagulation among patients with cancer and atrial fibrillation is challenging due to elevated risk of bleeding and stroke. We characterized use of oral anticoagulants among patients with cancer and non-valvular atrial fibrillation (NVAF). METHODS: We used Surveillance, Epidemiology, and End Results (SEER)-Medicare data and included patients with cancer aged ≥66 years with an incident diagnosis of NVAF from 2010 to 2016. We used a Cox proportional hazard model and multivariable logistic regression to identify factors associated with anticoagulant use versus no use and direct oral anticoagulants (DOACs) versus warfarin use, respectively. RESULTS: Of 27,702 patients with cancer and NVAF, 4469 (16.1%) used DOACs and 3577 (12.9%) used warfarin. Among 8046 anticoagulant users, DOACs use increased from 21.8% in 2011 to 76.2% in 2016, with a corresponding decline in warfarin use from 78.2% to 23.8%. Nearly 7 out of 10 patients with cancer and NVAF did not initiate anticoagulation in 2016. Anticoagulant use was more likely among those with higher CHA2DS2-VASc scores (hazard ratio [HR] 1.55, 95% confidence interval [CI] 1.27-1.90 for score ≥6 vs. 1) or with lower HAS-BLED scores (HR 1.96, 95% CI 1.67-2.30 for score 1 vs. ≥6). Among anticoagulant users, DOAC use was less likely than warfarin in those with higher CHA2DS2-VASc scores (odds ratio [OR] 0.53, 95% CI 0.33-0.84 for score ≥6 vs. 1). CONCLUSIONS: Nearly 7 out of 10 patients with cancer and NVAF did not receive anticoagulation. Use of DOACs increased from 2010 to 2016, with a corresponding decline in warfarin use. DOACs are used less than warfarin among those at higher risk of stroke.

Safety and effectiveness of apixaban versus warfarin for acute venous thromboembolism in patients with end-stage kidney disease: A national cohort study.

BACKGROUND: Patients with end-stage kidney disease (ESKD) are at significantly increased risk for both thrombosis and bleeding relative to those with normal renal function. The optimal therapy of venous thromboembolism (VTE) in patients with ESKD is unknown. OBJECTIVE: To compare the safety and effectiveness of apixaban relative to warfarin in patients with ESKD and acute VTE. DESIGN, SETTING AND PARTICIPANTS: New-user, active-comparator retrospective United States population-based cohort with inverse probability of treatment weighting, using the United States Renal Data System data from 2014 to 2018. We included adults with ESKD on hemodialysis or peritoneal dialysis who were newly initiated on apixaban or warfarin for an acute VTE. MAIN OUTCOME AND MEASURES: The coprimary outcomes were major bleeding, recurrent VTE, and all-cause mortality within 6 months of anticoagulant initiation. Secondary outcomes were intracranial hemorrhage and gastrointestinal bleeding. The primary analyses were based on intent-to-treat defined by the first drug received and accounted for competing risks of death. Sensitivity analyses included varied follow-up time, as-treated analyses, and dose-specific apixaban subgroups. RESULTS: The apixaban and warfarin cohorts included 2302 and 9263 patients, respectively. Apixaban was associated with a lower risk of major bleeding (hazard ratio [HR] 0.81, 95% confidence interval [CI]: 0.70-0.94), intracranial bleeding (HR 0.69, 95% CI 0.48-0.98), and gastrointestinal bleeding (HR 0.82, 95% CI 0.69-0.96). Recurrent VTE and all-cause mortality were not significantly different between the groups. CONCLUSION: Apixaban was associated with a lower risk of bleeding relative to warfarin when used to treat acute VTE in patients with ESKD on dialysis.

Use of Medications for Treating Anxiety or Depression among Testicular Cancer Survivors: A Multi-Institutional Study.

BACKGROUND: This study examined sociodemographic factors, cisplatin-related adverse health outcomes (AHO), and cumulative burden of morbidity (CBMPt) scores associated with medication use for anxiety and/or depression in testicular cancer survivors (TCS). METHODS: A total of 1,802 TCS who completed cisplatin-based chemotherapy ≥12 months previously completed questionnaires regarding sociodemographic features and cisplatin-related AHOs [hearing impairment, tinnitus, peripheral sensory neuropathy (PSN), and kidney disease]. A CBMPt score encompassed the number and severity of cisplatin-related AHOs. Multivariable logistic regression models assessed the relationship of individual AHOs and CBMPt with medication use for anxiety and/or depression. RESULTS: A total of 151 TCS (8.4%) used medications for anxiety and/or depression. No cisplatin-related AHOs were reported by 511 (28.4%) participants, whereas 622 (34.5%), 334 (18.5%), 287 (15.9%), and 48 (2.7%), respectively, had very low, low, medium, and high CBMPt scores. In the multivariable model, higher CBMPt scores were significantly associated with medication use for anxiety and/or depression (P < 0.0001). In addition, tinnitus (P = 0.0009), PSN (P = 0.02), and having health insurance (P = 0.05) were significantly associated with greater use of these medications, whereas being employed (P = 0.0005) and vigorous physical activity (P = 0.01) were significantly associated with diminished use. CONCLUSIONS: TCS with higher CBMPt scores had a higher probability of using medications for anxiety and/or depression, and conversely, those who were employed and physically active tended to have reduced use of these medications. IMPACT: Healthcare providers should encourage TCS to increase physical activity to improve both physical and mental health. Rehabilitation programs should assess work-related skills and provide career development counseling/training.

Residual Platinum Concentrations in Post-Cancer Chemotherapy and Healthy Control Populations Using an Automated, 96-Well Plate Method and Inductively Coupled Plasma Mass Spectrometry.

BACKGROUND: Platinating agents are among the most commonly used cytotoxic drugs worldwide. It is recognized that Pt concentration can remain significantly increased in serum up to 20 years after completion of chemotherapy, with levels related to late treatment effects. METHODS: A Freedom EVO® Tecan liquid handler was used for aliquoting 50 µL serum at 10-fold dilution into 96-well plates. The Teledyne MVX-7100 low-volume autosampler was used for sample introduction into an Agilent 7900 inductively coupled plasma mass spectrometry. There was <1.2 min needed between injections. Time to completion for a maximum batch size using two 96-well plates was approximately 3.5 h, including preparation and analysis. RESULTS: Imprecision was <15%, and the limit of quantification was set at 5 ng/L based on imprecision of 18.3%. Bias based on fortified samples ranged from 0% to -4.3% within the analytical measurement range of 5-10 000 ng/L. The nonparametric reference interval for platinum in serum using 147 residual clinical samples was determined to be 8-47 ng/L. Serum platinum concentrations in 675 enrolled patients having an average time since chemotherapy completion of 6.4 (± 5.5 years) ranged from 20.1 to 8252.4 ng/L. Among all patients, 633 (94%) had serum concentrations exceeding 47 ng/L, and 42 (6%) had serum platinum concentrations between 8 and 47 ng/L. CONCLUSIONS: This method used an automated liquid handler, a novel 96-well autosampler and 50 µL patient serum to quantify platinum levels. The method was successfully validated according to current clinical guidelines for laboratory developed tests.