A comparative effectiveness study of carotid intervention for long-term stroke prevention in patients with severe asymptomatic stenosis from a large integrated health system.

OBJECTIVE: The results of current prospective trials comparing the effectiveness of carotid endarterectomy (CEA) vs standard medical therapy for long-term stroke prevention in patients with asymptomatic carotid stenosis (ACS) will not be available for several years. In this study, we compared the observed effectiveness of CEA and standard medical therapy vs standard medical therapy alone to prevent ipsilateral stroke in a contemporary cohort of patients with ACS. METHODS: This cohort study was conducted in a large integrated health system in adult subjects with 70% to 99% ACS (no neurologic symptom within 6 months) with no prior ipsilateral carotid artery intervention. Causal inference methods were used to emulate a conceptual randomized trial using data from January 1, 2008, through December 31, 2017, for comparing the event-free survival over 96 months between two treatment strategies: (1) CEA within 12 months from cohort entry vs (2) no CEA (standard medical therapy alone). To account for both baseline and time-dependent confounding, inverse probability weighting estimation was used to derive adjusted hazard ratios, and cumulative risk differences were assessed based on two logistic marginal structural models for counterfactual hazards. Propensity scores were data-adaptively estimated using super learning. The primary outcome was ipsilateral anterior ischemic stroke. RESULTS: The cohort included 3824 eligible patients with ACS (mean age: 73.7 years, 57.9% male, 12.3% active smokers), of whom 1467 underwent CEA in the first year, whereas 2297 never underwent CEA. The median follow-up was 68 months. A total of 1760 participants (46%) died, 445 (12%) were lost to follow-up, and 158 (4%) experienced ipsilateral stroke. The cumulative risk differences for each year of follow-up showed a protective effect of CEA starting in year 2 (risk difference = 1.1%, 95% confidence interval: 0.5%-1.6%) and persisting to year 8 (2.6%, 95% confidence interval: 0.3%-4.8%) compared with patients not receiving CEA. CONCLUSIONS: In this contemporary cohort study of patients with ACS using rigorous analytic methodology, CEA appears to have a small but statistically significant effect on stroke prevention out to 8 years. Further study is needed to appropriately select the subset of patients most likely to benefit from intervention.

Adherence to cardiovascular medications and risk of cardiovascular disease in breast cancer patients: A causal inference approach in the Pathways Heart Study.

PURPOSE: Women with breast cancer (BC) are at high risk of developing cardiovascular disease (CVD). We examined adherence to CVD medications and their association with major CVD events over 14 years of follow-up in the Pathways Heart Study, a prospective study of 4,776 stage I-III BC patients diagnosed from 2005-2013. METHODS: Eligibility included being alive 6 months post-BC diagnosis, with dyslipidemia, hypertension, or diabetes at diagnosis along with ≥1 prior outpatient order or dispensing for a statin, anti-hypertensive, or diabetes medication, respectively, in the 30 months prior. Medication adherence was measured from pharmacy data to calculate cumulative average adherence (CAA). Incident heart failure (HF), ischemic heart disease (IHD), and stroke were determined via validated diagnosis and procedure codes. Working marginal structural models (MSM) fitted with inverse probability weighting evaluated the effect of adherence regimens on the hazards for each CVD event, while controlling for baseline and time-varying confounders. MSM parameterizations included: 1) CAA<100% versus CAA = 100% (ref), 2) CAA<80% versus CAA≥80% (ref) and 3) CAA<80% versus 80%≤CAA<100% versus CAA = 100%. RESULTS: Poor statin adherence (CAA<80%) was associated with higher risk of composite CVD (HR = 2.54; 95% CI: 1.09, 5.94) versus CAA≥80%. Poor statin adherence was also associated with a higher risk of stroke (HR = 8.13; 95% CI: 2.03, 32.51) but not risk of IHD and HF. Further, compared with perfect adherence (CAA = 100%), good adherence (80%≤CAA<100%) was associated with lower risk (HR = 0.35; 95% CI: 0.13, 0.92) while poor adherence (CAA<80%) was associated with higher risk of composite CVD (HR = 2.45; 95% CI: 1.05, 5.70). Levels of adherence to anti-hypertensives and diabetes medications had mixed or null associations with risk of CVD. CONCLUSIONS: Maintaining good adherence (≥80%) to statins after BC treatment is beneficial for cardiovascular health in patients with dyslipidemia. Future studies should determine factors associated with lower adherence to statins and ways to improve adherence.

Initial antiretroviral therapy regimen and risk of heart failure.

OBJECTIVES: Heart failure risk is elevated in people with HIV (PWH). We investigated whether initial antiretroviral therapy (ART) regimens influenced heart failure risk. DESIGN: Cohort study. METHODS: PWH who initiated an ART regimen between 2000 and 2016 were identified from three integrated healthcare systems. We evaluated heart failure risk by protease inhibitor, nonnucleoside reverse transcriptase inhibitors (NNRTI), and integrase strand transfer inhibitor (INSTI)-based ART, and comparing two common nucleotide reverse transcriptase inhibitors: tenofovir disoproxil fumarate (tenofovir) and abacavir. Follow-up for each pairwise comparison varied (i.e. 7 years for protease inhibitor vs. NNRTI; 5 years for tenofovir vs. abacavir; 2 years for INSTIs vs. PIs or NNRTIs). Hazard ratios were from working logistic marginal structural models, fitted with inverse probability weighting to adjust for demographics, and traditional cardiovascular risk factors. RESULTS: Thirteen thousand six hundred and thirty-four PWH were included (88% men, median 40 years of age; 34% non-Hispanic white, 24% non-Hispanic black, and 24% Hispanic). The hazard ratio (95% CI) were: 2.5 (1.5-4.3) for protease inhibitor vs. NNRTI-based ART (reference); 0.5 (0.2-1.8) for protease inhibitor vs. INSTI-based ART (reference); 0.1 (0.1-0.8) for NNRTI vs. INSTI-based ART (reference); and 1.7 (0.5-5.7) for tenofovir vs. abacavir (reference). In more complex models of cumulative incidence that accounted for possible nonproportional hazards over time, the only remaining finding was evidence of a higher risk of heart failure for protease inhibitor compared with NNRTI-based regimens (1.8 vs. 0.8%; P  = 0.002). CONCLUSION: PWH initiating protease inhibitors may be at higher risk of heart failure compared with those initiating NNRTIs. Future studies with longer follow-up with INSTI-based and other specific ART are warranted.

Development and Validation of a Diabetic Retinopathy Risk Stratification Algorithm.

OBJECTIVE: Although diabetic retinopathy is a leading cause of blindness worldwide, diabetes-related blindness can be prevented through effective screening, detection, and treatment of disease. The study goal was to develop risk stratification algorithms for the onset of retinal complications of diabetes, including proliferative diabetic retinopathy, referable retinopathy, and macular edema. RESEARCH DESIGN AND METHODS: Retrospective cohort analysis of patients from the Kaiser Permanente Northern California Diabetes Registry who had no evidence of diabetic retinopathy at a baseline diabetic retinopathy screening during 2008-2020 was performed. Machine learning and logistic regression prediction models for onset of proliferative diabetic retinopathy, diabetic macular edema, and referable retinopathy detected through routine screening were trained and internally validated. Model performance was assessed using area under the curve (AUC) metrics. RESULTS: The study cohort (N = 276,794) was 51.9% male and 42.1% White. Mean (±SD) age at baseline was 60.0 (±13.1) years. A machine learning XGBoost algorithm was effective in identifying patients who developed proliferative diabetic retinopathy (AUC 0.86; 95% CI, 0.86-0.87), diabetic macular edema (AUC 0.76; 95% CI, 0.75-0.77), and referable retinopathy (AUC 0.78; 95% CI, 0.78-0.79). Similar results were found using a simpler nine-covariate logistic regression model: proliferative diabetic retinopathy (AUC 0.82; 95% CI, 0.80-0.83), diabetic macular edema (AUC 0.73; 95% CI, 0.72-0.74), and referable retinopathy (AUC 0.75; 95% CI, 0.75-0.76). CONCLUSIONS: Relatively simple logistic regression models using nine readily available clinical variables can be used to rank order patients for onset of diabetic eye disease and thereby more efficiently prioritize and target screening for at risk patients.

Association of Glyburide and Subcutaneous Insulin With Perinatal Complications Among Women With Gestational Diabetes.

Importance: Nearly 30% of individuals with gestational diabetes (GDM) do not achieve glycemic control with lifestyle modification alone and require medication treatment. Oral agents, such as glyburide, have several advantages over insulin for the treatment of GDM, including greater patient acceptance; however, the effectiveness of glyburide for the treatment of GDM remains controversial. Objective: To compare the perinatal and neonatal outcomes associated with glyburide vs insulin using causal inference methods in a clinical setting with information on glycemic control. Design, Setting, and Participants: The population-based cohort study included patients with GDM who required medication treatment from 2007 to 2017 in Kaiser Permanente Northern California. Machine learning and rigorous casual inference methods with time-varying exposures were used to evaluate associations of exposure to glyburide vs insulin with perinatal outcomes. Data analysis was conducted from March 2018 to July 2017. Exposures: Time-varying exposure to glyburide vs insulin during pregnancy. Main Outcomes and Measures: Outcomes evaluated separately included neonatal hypoglycemia, jaundice, shoulder dystocia, respiratory distress syndrome (RDS), neonatal intensive care unit (NICU) admission, size-for-gestational age, and cesarean delivery. Inverse probability weighting (IPW) estimation was used to separately compare perinatal outcomes between those initiating glyburide and insulin. This approach was combined with Super Learning for propensity score estimation to account for both baseline and time-dependent confounding in both per-protocol (primary) and intention-to-treat (secondary) analyses to evaluate sustained exposure to the same therapy. Results: From 2007 to 2017, 11 321 patients with GDM (mean [SD] age, 32.9 [4.9] years) initiated glyburide or insulin during pregnancy. In multivariate models, the risk of neonatal respiratory distress was 2.03 (95% CI, 0.13-3.92) per 100 births lower and the risk of NICU admission was 3.32 (95% CI, 0.20-6.45) per 100 births lower after continuous exposure to glyburide compared with insulin. There were no statistically significant differences in glyburide vs insulin initiation in risk for neonatal hypoglycemia (0.85 [95% CI, -1.17 to 2.86] per 100 births), jaundice (0.02 [95% CI, -1.46 to 1.51] per 100 births), shoulder dystocia (-1.05 [95% CI, -2.71 to 0.62] per 100 births), or large-for-gestational age categories (-2.75 [95% CI, -6.31 to 0.80] per 100 births). Conclusions and Relevance: Using data from a clinical setting and contemporary causal inference methods, our findings do not provide evidence of a difference in the outcomes examined between patients with GDM initiating glyburide compared with those initiating insulin.

Association of Cardiovascular Outcomes and Mortality With Sustained Long-Acting Insulin Only vs Long-Acting Plus Short-Acting Insulin Treatment.

Importance: Cardiovascular events and mortality are the principal causes of excess mortality and health care costs for people with type 2 diabetes. No large studies have specifically compared long-acting insulin alone with long-acting plus short-acting insulin with regard to cardiovascular outcomes. Objective: To compare cardiovascular events and mortality in adults with type 2 diabetes receiving long-acting insulin who do or do not add short-acting insulin. Design, Setting, and Participants: This retrospective cohort study emulated a randomized experiment in which adults with type 2 diabetes who experienced a qualifying glycated hemoglobin A1c (HbA1c) level of 6.8% to 8.5% with long-acting insulin were randomized to continuing treatment with long-acting insulin (LA group) or adding short-acting insulin within 1 year of the qualifying HbA1c level (LA plus SA group). Retrospective data in 4 integrated health care delivery systems from the Health Care Systems Research Network from January 1, 2005, to December 31, 2013, were used. Analysis used inverse probability weighting estimation with Super Learner for propensity score estimation. Analyses took place from April 1, 2018, to June 30, 2019. Exposures: Long-acting insulin alone or with added short-acting insulin within 1 year from the qualifying HbA1c level. Main Outcomes and Measures: Mortality, cardiovascular mortality, acute myocardial infarction, stroke, and hospitalization for heart failure. Results: Among 57 278 individuals (39 279 with data on cardiovascular mortality) with a mean (SD) age of 60.6 (11.5) years, 53.6% men, 43.5% non-Hispanic White individuals, and 4 years of follow-up (median follow-up of 11 [interquartile range, 5-20] calendar quarters), the LA plus SA group was associated with increased all-cause mortality compared with the LA group (hazard ratio, 1.27; 95% CI, 1.05-1.49) and a decreased risk of acute myocardial infarction (hazard ratio, 0.89; 95% CI, 0.81-0.97). Treatment with long-acting plus short-acting insulin was not associated with increased risks of congestive heart failure, stroke, or cardiovascular mortality. Conclusions and Relevance: Findings of this retrospective cohort study suggested an increased risk of all-cause mortality and a decreased risk of acute myocardial infarction for the LA plus SA group compared with the LA group. Given the lack of an increase in major cardiovascular events or cardiovascular mortality, the increased all-cause mortality with long-acting plus short-acting insulin may be explained by noncardiovascular events or unmeasured confounding.

Comparison of Mortality and Major Cardiovascular Events Among Adults With Type 2 Diabetes Using Human vs Analogue Insulins.

Importance: The comparative cardiovascular safety of analogue and human insulins in adults with type 2 diabetes who initiate insulin therapy in usual care settings has not been carefully evaluated using machine learning and other rigorous analytic methods. Objective: To examine the association of analogue vs human insulin use with mortality and major cardiovascular events. Design, Setting, and Participants: This retrospective cohort study included 127 600 adults aged 21 to 89 years with type 2 diabetes at 4 health care delivery systems who initiated insulin therapy from January 1, 2000, through December 31, 2013. Machine learning and rigorous inference methods with time-varying exposures were used to evaluate associations of continuous exposure to analogue vs human insulins with mortality and major cardiovascular events. Data were analyzed from September 1, 2017, through June 30, 2018. Exposures: On the index date (first insulin dispensing), participants were classified as using analogue insulin with or without human insulin or human insulin only. Main Outcomes and Measures: Overall mortality, mortality due to cardiovascular disease (CVD), myocardial infarction (MI), stroke or cerebrovascular accident (CVA), and hospitalization for congestive heart failure (CHF) were evaluated. Marginal structural modeling (MSM) with inverse probability weighting was used to compare event-free survival in separate per-protocol analyses. Adjusted and unadjusted hazard ratios and cumulative risk differences were based on logistic MSM parameterizations for counterfactual hazards. Propensity scores were estimated using a data-adaptive approach (machine learning) based on 3 nested covariate adjustment sets. Sensitivity analyses were conducted to address potential residual confounding from unmeasured differences in risk factors across delivery systems. Results: The 127 600 participants (mean [SD] age, 59.4 [12.6] years; 68 588 men [53.8%]; mean [SD] body mass index, 32.3 [7.1]) had a median follow-up of 4 quarters (interquartile range, 3-9 quarters) and experienced 5464 deaths overall (4.3%), 1729 MIs (1.4%), 1301 CVAs (1.0%), and 3082 CHF hospitalizations (2.4%). There were no differences in adjusted hazard ratios for continuous analogue vs human insulin exposure during 10 quarters for overall mortality (1.15; 95% CI, 0.97-1.34), CVD mortality (1.26; 95% CI, 0.86-1.66), MI (1.11; 95% CI, 0.77-1.45), CVA (1.30; 95% CI, 0.81-1.78), or CHF hospitalization (0.93; 95% CI, 0.75-1.11). Conclusions and Relevance: Insulin-naive adults with type 2 diabetes who initiate and continue treatment with human vs analogue insulins had similar observed rates of major cardiovascular events, CVD mortality, and overall mortality.