Health Care Utilization and Costs Associated With Empagliflozin in Older Adults With Type 2 Diabetes.

OBJECTIVE: We compared health care resource utilization (HCRU) and costs for inpatient and outpatient services and dispensed medications in older adults with type 2 diabetes initiating empagliflozin versus dipeptidyl peptidase 4 inhibitors (DPP-4is). RESEARCH DESIGN AND METHODS: The study population included U.S. Medicare fee-for-service beneficiaries with diabetes (age ≥65 years) initiating empagliflozin or DPP-4is (August 2014 to September 2018). We estimated rate ratios (RRs) for HCRU outcomes using zero-inflated negative binomial regression and per-member per-year (PMPY) cost differences using generalized linear model with gamma distributions, overall and stratified by baseline cardiovascular disease (CVD), after adjusting for 143 baseline covariates using 1:1 propensity score matching. RESULTS: We identified 23,335 matched pairs (mean age 72 years, 51% with baseline CVD). HCRU rates were lower in empagliflozin versus DPP-4i initiators (number of inpatient days, RR 0.89 [95% CI 0.82, 0.97]; number of emergency department [ED] visits, 0.86 [0.82, 0.91]; number of hospitalizations, 0.86 [0.79, 0.93]; number of office visits, 0.96 [0.95, 0.98]). Inpatient cost (-$713 PMPY [95% CI -847, -579), outpatient cost (-$198 PMPY[-272, -124]), and total cost of care (-$1,109 PMPY [-1,478, -739]) were lower for empagliflozin versus DPP-4is, although diabetes medication cost was higher in empagliflozin initiators ($454 PMPY [95% CI 284, 567]). In the CVD subgroup, total cost was lower for empagliflozin initiators (-$2,005 PMPY [-2,451, -1,337]), while the difference was attenuated in the non-CVD subgroup (-$296 PMPY[-740, 148]). CONCLUSIONS: Among older adults with diabetes, empagliflozin was associated with a lower number of inpatient days, hospitalizations, ED visits, and office visits and with lower costs of care compared with DPP-4is, especially in those with history of CVD.

Effectiveness and safety of empagliflozin: final results from the EMPRISE study.

AIMS/HYPOTHESIS: Limited evidence exists on the comparative safety and effectiveness of empagliflozin against alternative glucose-lowering medications in individuals with type 2 diabetes with the broad spectrum of cardiovascular risk. The EMPagliflozin compaRative effectIveness and SafEty (EMPRISE) cohort study was designed to monitor the safety and effectiveness of empagliflozin periodically for a period of 5 years with data collection from electronic healthcare databases. METHODS: We identified individuals ≥18 years old with type 2 diabetes who initiated empagliflozin or dipeptidyl peptidase-4 inhibitors (DPP-4i) from 2014 to 2019 using US Medicare and commercial claims databases. After 1:1 propensity score matching using 143 baseline characteristics, we identified four a priori-defined effectiveness outcomes: (1) myocardial infarction (MI) or stroke; (2) hospitalisation for heart failure (HHF); (3) major adverse cardiovascular events (MACE); and (4) cardiovascular mortality or HHF. Safety outcomes included lower-limb amputations, non-vertebral fractures, diabetic ketoacidosis (DKA), acute kidney injury (AKI), severe hypoglycaemia, retinopathy progression, and short-term kidney and bladder cancers. We estimated HRs and rate differences (RDs) per 1000 person-years, overall and stratified by age, sex, baseline atherosclerotic cardiovascular disease (ASCVD) and heart failure. RESULTS: We identified 115,116 matched pairs. Compared with DPP-4i, empagliflozin was associated with lower risks of MI/stroke (HR 0.88 [95% CI 0.81, 0.96]; RD -2.08 [95% CI (-3.26, -0.90]), HHF (HR 0.50 [0.44, 0.56]; RD -5.35 [-6.22, -4.49]), MACE (HR 0.73 [0.62, 0.86]; RD -6.37 [-8.98, -3.77]) and cardiovascular mortality/HHF (HR 0.57 [0.47, 0.69]; RD -10.36 [-12.63, -8.12]). Absolute benefits were larger in older individuals and in those with ASCVD/heart failure. Empagliflozin was associated with an increased risk of DKA (HR 1.78 [1.44, 2.19]; RD 1.59 [1.08, 2.09]); decreased risks of AKI (HR 0.62 [0.54, 0.72]; RD -2.39 [-3.08, -1.71]), hypoglycaemia (HR 0.75 [0.67, 0.84]; RD -2.46 [-3.32, -1.60]) and retinopathy progression (HR 0.78 [0.63, 0.96)]; RD -9.49 [-16.97, -2.10]); and similar risks of other safety events. CONCLUSIONS/INTERPRETATION: Empagliflozin relative to DPP-4i was associated with risk reductions of MI or stroke, HHF, MACE and the composite of cardiovascular mortality or HHF. Absolute risk reductions were larger in older individuals and in those who had history of ASCVD or heart failure. Regarding the safety outcomes, empagliflozin was associated with an increased risk of DKA and lower risks of AKI, hypoglycaemia and progression to proliferative retinopathy, with no difference in the short-term risks of lower-extremity amputation, non-vertebral fractures, kidney and renal pelvis cancer, and bladder cancer.

Cardiorenal effectiveness of empagliflozin vs. glucagon-like peptide-1 receptor agonists: final-year results from the EMPRISE study.

BACKGROUND: No randomized clinical trials have directly compared the cardiorenal effectiveness of empagliflozin and GLP-1RA agents with demonstrated cardioprotective effects in patients with a broad spectrum of cardiovascular risk. We reported the final-year results of the EMPRISE study, a monitoring program designed to evaluate the cardiorenal effectiveness of empagliflozin across broad patient subgroups. METHODS: We identified patients ≥ 18 years old with type 2 diabetes who initiated empagliflozin or GLP-1RA from 2014 to 2019 using US Medicare and commercial claims databases. After 1:1 propensity score matching using 143 baseline characteristics, we evaluated risks of outcomes including myocardial infarction (MI) or stroke, hospitalization for heart failure (HHF), major adverse cardiovascular events (MACE - MI, stroke, or cardiovascular mortality), a composite of HHF or cardiovascular mortality, and progression to end-stage kidney disease (ESKD) (in patients with chronic kidney disease stages 3-4). We estimated hazard ratios (HR) and rate differences (RD) per 1,000 person-years, overall and within subgroups of age, sex, baseline atherosclerotic cardiovascular disease (ASCVD), and heart failure (HF). RESULTS: We identified 141,541 matched pairs. Compared with GLP-1RA, empagliflozin was associated with similar risks of MI or stroke [HR: 0.99 (0.92, 1.07); RD: -0.23 (-1.25, 0.79)], and lower risks of HHF [HR: 0.50 (0.44, 0.56); RD: -2.28 (-2.98, -1.59)], MACE [HR: 0.90 (0.82, 0.99); RD: -2.54 (-4.76, -0.32)], cardiovascular mortality or HHF [HR: 0.77 (0.69, 0.86); RD: -4.11 (-5.95, -2.29)], and ESKD [0.75 (0.60, 0.94); RD: -6.77 (-11.97, -1.61)]. Absolute risk reductions were larger in older patients and in those with baseline ASCVD/HF. They did not differ by sex. CONCLUSIONS: The cardiovascular benefits of empagliflozin vs. cardioprotective GLP-1RA agents were larger in older patients and in patients with history of ASCVD or HF, while they did not differ by sex. In patients with advanced CKD, empagliflozin was associated with risk reductions of progression to ESKD.

Stratified analysis in comparative effectiveness studies that emulate randomized trials.

PURPOSE: For observational cohort studies that employ matching by propensity scores (PS), preliminary stratification by consequential predictors of outcome better emulates stratified randomization and potentially reduces variance and bias through relaxed dependence on modeling assumptions. We assessed the impact of pre-stratification in two real-life examples. For both, prior evidence from placebo-controlled randomized clinical trials (RCTs) suggested small or no risk reduction, but observational analysis suggested protection, presumably the result of confounding bias. STUDY DESIGN AND SETTING: The study populations consisted of Medicare beneficiaries (2014-18) with type 2 diabetes initiating either (i) empagliflozin versus dipeptidyl peptidase-4 inhibitors (DPP-4i) or (ii) empagliflozin versus glucagon-like peptide-1 receptor agonists (GLP-1RA). The outcome was myocardial infarction or stroke. We estimated hazard ratios (HR) and rate differences (RD) after controlling for 143 pre-exposure covariates via 1:1 PS matching after (1) PS estimation in the total cohort (total-cohort PS-matching) and (2) PS estimation separately by baseline cardiovascular disease (stratified PS matching). RESULTS: Stratified PS matching resulted in HRs that exceeded those from total-cohort PS-matching by 13% and 9%, respectively, for the comparisons of empagliflozin to DPP-4i and GLP-1RA. Against both comparators, HRs and RDs after stratified PS matching were closer to the null, with slightly higher variances (2%-3%) than those after total-cohort PS matching. CONCLUSION: Stratified PS matching produced effect estimates closer to the expected trial findings than total-cohort PS matching. The price paid in increased variance was minimal.

Iterative Causal Forest: A Novel Algorithm for Subgroup Identification.

Precisely and efficiently identifying subgroups with heterogeneous treatment effects (HTEs) in real-world evidence studies remains a challenge. Based on the causal forest (CF) method, we developed an iterative CF (iCF) algorithm to identify HTEs in subgroups defined by important variables. Our method iteratively grows different depths of the CF with important effect modifiers, performs plurality votes to obtain decision trees (subgroup decisions) for a family of CFs with different depths, then finds the cross-validated subgroup decision that best predicts the treatment effect as a final subgroup decision. We simulated 12 different scenarios and showed that the iCF outperformed other machine learning methods for interaction/subgroup identification in the majority of scenarios assessed. Using a 20% random sample of fee-for-service Medicare beneficiaries initiating sodium-glucose cotransporter-2 inhibitors (SGLT2i) or glucagon-like peptide-1 receptor agonists (GLP1RA), we implemented the iCF to identify subgroups with HTEs for hospitalized heart failure. Consistent with previous studies suggesting patients with heart failure benefit more from SGLT2i, iCF successfully identified such a subpopulation with HTEs and additive interactions. The iCF is a promising method for identifying subgroups with HTEs in real-world data where the potential for unmeasured confounding can be limited by study design.

Risk of Severe Hypoglycemia With Newer Second-line Glucose-lowering Medications in Older Adults With Type 2 Diabetes Stratified by Known Indicators of Hypoglycemia Risk.

BACKGROUND: Severe hypoglycemia is associated with adverse clinical outcomes. We evaluated the risk of severe hypoglycemia in older adults initiating newer glucose-lowering medications overall and across strata of known indicators of high hypoglycemia risk. METHODS: We conducted a comparative-effectiveness cohort study of older adults aged >65 years with type 2 diabetes initiating sodium-glucose cotransporter 2 inhibitors (SGLT2i) versus dipeptidyl peptidase-4 inhibitors (DPP-4i) or SGLT2i versus glucagon-like peptide-1 receptor agonists (GLP-1RA) using Medicare claims (3/2013-12/2018) and Medicare-linked-electronic health records. We identified severe hypoglycemia requiring emergency or inpatient visits using validated algorithms. After 1:1 propensity score matching, we estimated hazard ratios (HR) and rate differences (RD) per 1,000 person-years. Analyses were stratified by baseline insulin, sulfonylurea, cardiovascular disease (CVD), chronic kidney disease (CKD), and frailty. RESULTS: Over a median follow-up of 7 (interquartile range: 4-16) months, SGLT2i was associated with a reduced risk of hypoglycemia versus DPP-4i (HR 0.75 [0.68, 0.83]; RD -3.21 [-4.29, -2.12]), and versus GLP-1RA (HR 0.90 [0.82, 0.98]; RD -1.33 [-2.44, -0.23]). RD for SGLT2i versus DPP-4i was larger in patients using baseline insulin than in those not, although HRs were similar. In patients using baseline sulfonylurea, the risk of hypoglycemia was lower in SGLT2i versus DPP-4i (HR 0.57 [0.49, 0.65], RD -6.80 [-8.43, -5.16]), while the association was near-null in those without baseline sulfonylurea. Results stratified by baseline CVD, CKD and frailty were similar to the overall cohort findings. Findings for the GLP-1RA comparison were similar. CONCLUSIONS: SGLT2i was associated with a lower hypoglycemia risk versus incretin-based medications, with larger associations in patients using baseline insulin or sulfonylurea.

Comparative Effectiveness of Empagliflozin vs Liraglutide or Sitagliptin in Older Adults With Diverse Patient Characteristics.

Importance: Limited evidence is available on the comparative effectiveness of empagliflozin vs alternative second-line glucose-lowering agents in patients with type 2 diabetes (T2D) receiving routine care who have a broad spectrum of cardiorenal risk. Objective: To evaluate the association of empagliflozin with cardiovascular outcomes relative to liraglutide and sitagliptin, stratified by age, sex, baseline atherosclerotic cardiovascular disease (ASCVD), heart failure (HF), and chronic kidney disease (CKD). Design, Setting, and Participants: This retrospective comparative effectiveness cohort study used deidentified Medicare claims data from August 1, 2014, to September 30, 2018, with follow-up from drug initiation until treatment changes, death, or gap in Medicare enrollment (>30 days). Data analysis was performed from October 1, 2021, to April 30, 2022. Medicare fee-for-service beneficiaries older than 65 years with T2D were included. A total of 45 788 patients (22 894 propensity score-matched pairs initiating treatment with either empagliflozin or liraglutide) were included in cohort 1, and 45 624 patients (22 812 propensity score-matched pairs initiating treatment with either empagliflozin or sitagliptin) were included in cohort 2. Exposures: Empagliflozin vs liraglutide (cohort 1) or empagliflozin vs sitagliptin (cohort 2). Main Outcomes and Measures: Primary outcomes were (1) modified major adverse cardiovascular events (MACEs), including a composite of myocardial infarction, stroke, and all-cause mortality, and (2) hospitalization for heart failure (HHF). Hazard ratios (HRs) and rate differences (RDs) per 1000 person-years were estimated, adjusting for 143 baseline covariates using 1:1 propensity score matching. Results: Among 45 788 patients in cohort 1, the mean (SD) age was 71.9 (5.1) years; 23 396 patients (51.1%) were female, 22 392 (48.9%) were male, and 38 049 (83.1%) were White. Among 45 624 patients in cohort 2, the mean (SD) age was 72.1 (5.1) years; 21 418 patients (46.9%) were female, 24 206 (53.1%) were male, and 37 814 (82.9%) were White. Relative to patients initiating liraglutide, those initiating empagliflozin had a similar risk of the modified MACE outcome (HR, 0.90; 95% CI, 0.79-1.03) and a reduced risk of HHF (HR, 0.66; 95% CI, 0.52-0.82). Across subgroups, empagliflozin was associated with a lower risk of the modified MACE outcome in patients with a history of ASCVD (HR, 0.83; 95% CI, 0.71-0.98) and HF (HR, 0.77; 95% CI, 0.60-1.00) compared with liraglutide, and potential heterogeneity in estimates was observed by sex (male: HR, 0.85 [95% CI, 0.71-1.01]; female: HR, 1.16 [95% CI, 0.94-1.42]; P = .02 for homogeneity). However, reductions in the risk of HHF were observed across most subgroups (eg, ASCVD: HR, 0.66 [95% CI, 0.51-0.85]; HF: HR, 0.66 [95% CI, 0.49-0.88]). Compared with sitagliptin, empagliflozin was associated with reduced risks of the modified MACE outcome (HR, 0.68; 95% CI, 0.60-0.77) and HHF (HR, 0.45; 95% CI, 0.36-0.56), which were consistent across all subgroups. Absolute benefits of empagliflozin vs sitagliptin were larger in patients with a history of ASCVD (modified MACE: RD, -17.6 [95% CI, -24.9 to -10.4]; HHF: RD, -16.7 [95% CI, -21.7 to -11.9]), HF (modified MACE: RD, -41.1 [95% CI, -59.9 to -22.6]; HHF: RD, -50.4 [95% CI, -67.5 to -33.9]), or CKD (modified MACE: RD, -26.7 [95% CI, -41.3 to -12.3]; HHF: RD, -31.9 [95% CI, -43.5 to -20.8]). Conclusions and Relevance: In this comparative effectiveness study of older adults, empagliflozin was associated with a lower risk of HHF (relative to both liraglutide and sitagliptin) and the modified MACE outcome (relative to sitagliptin), with larger absolute benefits in patients with established cardiorenal diseases. These findings suggest that older adults with T2D might benefit more from empagliflozin vs liraglutide or sitagliptin with respect to the risk of HHF; with respect to the risk of MACEs, empagliflozin might be preferable to liraglutide only in patients with cardiovascular disease history and to sitagliptin across all patient subgroups.

Evaluating Confounding Control in Estimations of Influenza Antiviral Effectiveness in Electronic Health Plan Data.

Observational studies of oseltamivir use and influenza complications could suffer from residual confounding. Using negative control risk periods and a negative control outcome, we examined confounding control in a health-insurance-claims-based study of oseltamivir and influenza complications (pneumonia, all-cause hospitalization, and dispensing of an antibiotic). Within the Food and Drug Administration's Sentinel System, we identified individuals aged ≥18 years who initiated oseltamivir use on the influenza diagnosis date versus those who did not, during 3 influenza seasons (2014-2017). We evaluated primary outcomes within the following 1-30 days (the primary risk period) and 61-90 days (the negative control period) and nonvertebral fractures (the negative control outcome) within days 1-30. We estimated propensity-score-matched risk ratios (RRs) per season. During the 2014-2015 influenza season, oseltamivir use was associated with a reduction in the risk of pneumonia (RR = 0.72, 95% confidence interval (CI): 0.70, 0.75) and all-cause hospitalization (RR = 0.54, 95% CI: 0.53, 0.55) in days 1-30. During days 61-90, estimates were near-null for pneumonia (RR = 1.04, 95% CI: 0.95, 1.15) and hospitalization (RR = 0.94, 95% CI: 0.91, 0.98) but slightly increased for antibiotic dispensing (RR = 1.14, 95% CI: 1.08, 1.21). The RR for fractures was near-null (RR = 1.09, 95% CI: 0.99, 1.20). Estimates for the 2016-2017 influenza season were comparable, while the 2015-2016 season had conflicting results. Our study suggests minimal residual confounding for specific outcomes, but results differed by season.

Cardiovascular Effectiveness of Sodium-Glucose Cotransporter 2 Inhibitors and Glucagon-Like Peptide-1 Receptor Agonists in Older Patients in Routine Clinical Care With or Without History of Atherosclerotic Cardiovascular Diseases or Heart Failure.

Background Randomized trials demonstrate the cardioprotective effects of sodium-glucose cotransporter 2 inhibitors (SGLT2i) and glucagon-like peptide-1 receptor agonists (GLP-1RA). We evaluated their relative cardiovascular effectiveness in routine care populations with a broad spectrum of atherosclerotic cardiovascular diseases (CVDs) or heart failure (HF). Methods and Results We identified Medicare beneficiaries from 2013 to 2017, aged >65 years, initiating SGLT2i (n=24 747) or GLP-1RA (n=22 596) after a 1-year baseline. On the basis of diagnoses during baseline, we classified patients into: (1) no HF or CVD, (2) HF but no CVD, (3) no HF but CVD, and (4) both HF and CVD. We identified hospitalized HF and atherosclerotic CVD outcomes from drug initiation until treatment changes, death, or disenrollment. We estimated propensity score-weighted 2-year risk ratios (RRs) and risk differences, accounting for measured confounding, informative censoring, and competing risk. In patients with no CVD or HF, SGLT2i reduced the hospitalized HF risk compared with GLP-1RA (propensity score-weighted RR, 0.65; 95% CI, 0.43-0.96). The association was strongest in those who had HF but no CVD (RR, 0.48; 95% CI, 0.25-0.85). The combined myocardial infarction, stroke, and mortality outcome risk was slightly higher for SGLT2i compared with GLP-1RA in those without CVD or HF (RR, 1.31; 95% CI, 1.09-1.56). The association was favorable toward SGLT2i in subgroups with a history of HF. Conclusions SGLT2i reduced the cardiovascular risk versus GLP-1RA in patients with a history of HF but no CVD. Atherosclerotic CVD events were less frequent with GLP-1RA in those without prior CVD or HF.

Sodium-Glucose Cotransporter-2 Inhibitors Versus Glucagon-like Peptide-1 Receptor Agonists and the Risk for Cardiovascular Outcomes in Routine Care Patients With Diabetes Across Categories of Cardiovascular Disease.

BACKGROUND: Both sodium-glucose cotransporter-2 (SGLT2) inhibitors and glucagon-like peptide-1 receptor agonists (GLP-1 RAs) have shown cardiovascular benefits in placebo-controlled trials of patients with type 2 diabetes (T2D) and established cardiovascular disease (CVD). OBJECTIVE: To evaluate whether SGLT2 inhibitors and GLP-1 RAs are associated with differential cardiovascular benefit among T2D patients with and without CVD. DESIGN: Population-based cohort study. SETTING: Medicare and 2 U.S. commercial claims data sets (April 2013 to December 2017). PARTICIPANTS: 1:1 propensity score-matched adult T2D patients with and without CVD (52 901 and 133 139 matched pairs) initiating SGLT2 inhibitor versus GLP-1 RA therapy. MEASUREMENTS: Primary outcomes were myocardial infarction (MI) or stroke hospitalization and hospitalization for heart failure (HHF). Pooled hazard ratios (HRs) and rate differences (RDs) per 1000 person-years were estimated, with 95% CIs, controlling for 138 preexposure covariates. RESULTS: The initiation of SGLT2 inhibitor versus GLP-1 RA therapy was associated with a slightly lower risk for MI or stroke in patients with CVD (HR, 0.90 [95% CI, 0.82 to 0.98]; RD, -2.47 [CI, -4.45 to -0.50]) but similar risk in those without CVD (HR, 1.07 [CI, 0.97 to 1.18]; RD, 0.38 [CI, -0.30 to 1.07]). The initiation of SGLT2 inhibitor versus GLP-1 RA therapy was associated with reductions in HHF risk regardless of baseline CVD in patients with CVD (HR, 0.71 [CI, 0.64 to 0.79]; RD, -4.97 [CI, -6.55 to -3.39]) and in those without CVD (HR, 0.69 [CI, 0.56 to 0.85]; RD, -0.58 [CI, -0.91 to -0.25]). LIMITATION: Treatment selection was not randomized. CONCLUSION: Use of SGLT2 inhibitors versus GLP-1 RAs was associated with consistent reductions in HHF risk among T2D patients with and without CVD, although the absolute benefit was greater in patients with CVD. There were no large differences in risk for MI or stroke among T2D patients with and without CVD. PRIMARY FUNDING SOURCE: Division of Pharmacoepidemiology and Pharmacoeconomics, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School.

Renin-Angiotensin-Aldosterone System-based Antihypertensive Agents and the Risk of Colorectal Cancer Among Medicare Beneficiaries.

BACKGROUND: Biologic evidence suggests that angiotensin II may play a role in tumor progression or growth. We compared the short-term colorectal cancer (CRC) risk among initiators of angiotensin-converting enzyme inhibitors (ACEI) or angiotensin receptor blockers (ARB) versus guideline-recommended clinical alternatives (beta blockers, calcium channel blockers [CCB], and thiazides). METHODS: We conducted a new-user cohort study on U.S. Medicare beneficiaries aged over 65 years, who initiated antihypertensive monotherapy during 2007-2013 and were free of cancer diagnosis before drug initiation. Follow-up began 6 months postinitiation to allow time for the diagnostic delay. We estimated hazard ratios (HR) with 95% confidence intervals (CI) using propensity score weighted Cox regression, overall and stratified by time since drug initiation, and 5-year cumulative risk differences (RD) using Kaplan-Meier estimator. We assessed the potential for unmeasured confounding using supplemental data from Medicare Current Beneficiary Survey. RESULTS: For analyses without censoring for treatment changes, we observed 532 CRC events among 111,533 ACEI/ARB initiators. After a median follow-up of 2.2 years (interquartile range: 1.0-3.7), CRC risk was similar between ACEI/ARB and active comparators, with adjusted HRs of 1.0 (95% CI = 0.85, 1.1) for ACEI/ARB versus beta blockers, 1.2 (95% CI = 0.97, 1.4) for ACEI/ARB versus CCB and 1.0 (95% CI = 0.80, 1.3) for ACEI/ARB versus thiazide. Five-year RDs and as-treated analyses, which censored follow-up at medication changes, produced similar findings. CONCLUSIONS: Based on real-world antihypertensive utilization patterns in Medicare beneficiaries, our study suggests no association between ACEI/ARB initiation and the short-term CRC risk.

Counterpoint: Keeping the Demons at Bay When Handling Time-Varying Exposures-Beyond Avoiding Immortal Person-Time.

The potential for immortal time bias is pervasive in epidemiologic studies with left truncation or time-varying exposures. Unlike other biases in epidemiologic research (e.g., measurement bias, confounding due to unmeasured factors, and selection based on unmeasured predictors of the outcome), immortal time bias can and should be avoided by the correct assignment of person-time during follow up. However, even when handing person-time correctly, allowing late entry into a study or into an exposure group can open the door to more insidious sources of bias, some of which we explore here. Clear articulation of the study question, including the treatment plans of interest, can provide navigation around these sources of bias and elucidate the assumptions needed for inference given the available data. Here, we use simulated data to illustrate the assumptions required under various approaches to estimate the effect of a time-varying treatment and describe how these assumptions relate to the assumptions necessary to estimate single sample rates and risks in settings with censoring and truncation.

Evaluating the association between adjuvant chemotherapy and function-related adverse events among older patients with early stage breast cancer.

PURPOSE: The incidence of treatment-related toxicity for adjuvant chemotherapy in breast cancer is well documented in clinical trials. However, the effect of chemotherapy on functional outcomes in older patients is less well known. We identified a cohort of older women diagnosed with early stage breast cancer to examine the association between exposure to chemotherapy and a claims-based measure of function-related adverse events (FAE). METHODS: Using the Surveillance, Epidemiology, and End Results (SEER)-Medicare dataset, we identified women aged ≥66 diagnosed with stage I or II breast cancer from 2004 to 2011. FAE were defined as one or more claims suggestive of functional impairment within 24months following chemotherapy including claims for durable medical equipment and skilled care. Women who did not receive chemotherapy were weighted to reflect the covariate distribution of chemotherapy recipients using propensity score weighting for age, stage, baseline healthcare utilization, and comorbidities. RESULTS: The cohort included 44,626 patients, 6892 (15%) received chemotherapy. 19% of the population experienced ≥1 FAE. After propensity weighting, chemotherapy was associated with a small increased risk of FAEs (HR 1.12, 95% confidence interval: 1.04, 1.20). Results were similar in patients 75years and older versus younger patients. In the chemotherapy group, the highest risk of FAE occurred in the first 3months, but persisted through follow-up. CONCLUSIONS: Exposure to chemotherapy was associated with a small increased risk of FAE which did not vary by age. These data can be used to inform treatment decision making for older patients with breast cancer who are eligible for adjuvant chemotherapy.

The Breast and Cervical Cancer Early Detection Program, Medicaid, and breast cancer outcomes among Ohio's underserved women.

BACKGROUND: As an organized screening program, the national Breast and Cervical Cancer Early Detection Program (BCCEDP) was launched in the early 1990s to improve breast cancer outcomes among underserved women. To analyze the impact of the BCCEDP on breast cancer outcomes in Ohio, this study compared cancer stages and mortality across BCCEDP participants, Medicaid beneficiaries, and "all others." METHODS: This study linked data across the Ohio Cancer Incidence Surveillance System, Medicaid, the BCCEDP database, death certificates, and the US Census and identified 26,426 women aged 40 to 64 years who had been diagnosed with incident invasive breast cancer during the years 2002-2008 (deaths through 2010). The study groups were as follows: BCCEDP participants (1-time or repeat users), Medicaid beneficiaries (women enrolled in Medicaid before their cancer diagnosis [Medicaid/prediagnosis] or around the time of their cancer diagnosis [Medicaid/peridiagnosis]), and all others (women identified as neither BCCEDP participants nor Medicaid beneficiaries). The outcomes included advanced-stage cancer at diagnosis and mortality. A multivariable logistic and survival analysis was conducted to examine the independent association between the BCCEDP and Medicaid status and the outcomes. RESULTS: The percentage of women presenting with advanced-stage disease was highest among women in the Medicaid/peridiagnosis group (63.4%) and lowest among BCCEDP repeat users (38.6%). With adjustments for potential confounders and even in comparison with Medicaid/prediagnosis beneficiaries, those in the Medicaid/peridiagnosis group were twice as likely to be diagnosed with advanced-stage disease (adjusted odds ratio, 2.20; 95% confidence interval, 1.83-2.66). CONCLUSIONS: Medicaid/peridiagnosis women are at particularly high risk to be diagnosed with advanced-stage disease. Efforts to reduce breast cancer disparities must target this group of women before they present to Medicaid. Cancer 2017;123:3097-106. © 2017 American Cancer Society.

Effect of glucagon-like peptide-1 receptor agonists and dipeptidyl peptidase-4 inhibitors on colorectal cancer incidence and its precursors.

AIMS: Incretin-based antihyperglycemic therapies increase intestinal mucosal expansion and polyp growth in mouse models. We aimed to evaluate the effect of dipeptidyl peptidase-4 inhibitors (DPP-4i) or glucagon-like peptide-1 receptor agonists (GLP-1ra) initiation on colorectal cancer incidence. METHODS: We conducted a cohort study on US Medicare beneficiaries over age 66 from 2007 to 2013 without prevalent cancer. We identified three active-comparator and new-user cohorts: DPP-4i versus thiazolidinediones (TZD), DPP-4i versus sulphonylureas (SU), and GLP-1ra versus long acting insulin (LAI). Follow-up started from 6 months post-second prescription and ended 6 months after stopping (primary as-treated analysis). We estimated hazard ratios (HR) and 95 % confidence intervals (CI) for incident colorectal cancer adjusting for measured confounders using propensity score weighting. RESULTS: The median duration of treatment ranged 0.7-0.9 years among DPP-4i cohorts. Based on 104 events among 39,334 DPP-4i and 63 events among 25,786 TZD initiators, there was no association between DPP-4i initiation and colorectal cancer (adjusted HR = 1.17 (CI 0.88, 1.71)). There were 73 events among 27,047 DPP-4i and 266 events among 76,012 SU initiators with the adjusted HR 0.98 (CI 0.74, 1.30). We identified 5600 GLP-1ra and 54,767 LAI initiators and the median duration of treatment was 0.8 and 1.2 years, respectively. The adjusted HR was 0.82 (CI 0.42, 1.58) based on <11 events among GLP-1ra versus 276 events among LAI initiators. CONCLUSION: Although limited by the short duration of treatment, our analyses based on real-world drug utilization patterns provide evidence of no short-term effect of incretin-based agents on colorectal cancer.

A comparison of the effects of epidural analgesia versus traditional pain management on outcomes after gastric cancer resection: a population-based study.

BACKGROUND AND OBJECTIVES: Epidural analgesia may increase survival after cancer surgery by reducing recurrence. This population-based study compared survival and treated recurrence after gastric cancer resection between patients receiving epidurals and those who did not. METHODS: We used the linked federal Surveillance, Epidemiology, and End Results Program/Medicare database to identify patients aged 66 years or older with nonmetastatic gastric carcinoma diagnosed 1996 to 2005 who underwent resection. Exclusions included diagnosis at autopsy, no Medicare Part B, familial cancer syndrome, emergency surgery, and laparoscopic procedures. Epidurals were identified by Current Procedural Terminology codes. Treated recurrence was defined as chemotherapy greater than or equal to 16 months and/or radiation greater than or equal to 12 months after surgery. Recurrence was compared by conditional logistic regression. Survival was compared via marginal Cox proportional hazards regression model. RESULTS: We identified 2745 patients, 766 of whom had epidural codes. Patients receiving epidurals were more likely to have regional disease, be white, and live in areas with relatively high socioeconomic status. Overall treated recurrence was 25.6% (27.5% epidural and 24.9% nonepidural). In the adjusted logistic regression, there was no difference in recurrence (odds ratio, 1.40; 95% confidence interval [CI], 0.96-2.05). Median survival did not differ: 28.1 months (95% CI, 24.8-32.3) in the epidural versus 27.4 months (95% CI, 24.8-30.0) in the nonepidural groups. The marginal Cox models showed no association between epidural use and mortality (adjusted hazard ratio, 0.93; 95% CI, 0.84-1.03). CONCLUSIONS: There was no difference between groups regarding treated recurrence or survival. Whether this is true or simply a result of insufficient power is unclear. Prospective studies are needed to provide stronger evidence.