Assessing response bias from missing quality of life data: The Heckman method

BACKGROUND: The objective of this study was to demonstrate the use of the Heckman two-step method to assess and correct for bias due to missing health related quality of life (HRQL) surveys in a clinical study of acute coronary syndrome (ACS) patients. METHODS: We analyzed data from 2,733 veterans with a confirmed diagnosis of acute coronary syndromes (ACS), including either acute myocardial infarction or unstable angina. HRQL outcomes were assessed by the Short-Form 36 (SF-36) health status survey which was mailed to all patients who were alive 7 months following ACS discharge. We created multivariable models of 7-month post-ACS physical and mental health status using data only from the 1,660 survey respondents. Then, using the Heckman method, we modeled survey non-response and incorporated this into our initial models to assess and correct for potential bias. We used logistic and ordinary least squares regression to estimate the multivariable selection models. RESULTS: We found that our model of 7-month mental health status was biased due to survey non-response, while the model for physical health status was not. A history of alcohol or substance abuse was no longer significantly associated with mental health status after controlling for bias due to non-response. Furthermore, the magnitude of the parameter estimates for several of the other predictor variables in the MCS model changed after accounting for bias due to survey non-response. CONCLUSION: Recognition and correction of bias due to survey non-response changed the factors that we concluded were associated with HRQL seven months following hospital admission for ACS as well as the magnitude of some associations. We conclude that the Heckman two-step method may be a valuable tool in the assessment and correction of selection bias in clinical studies of HRQL

An Australian longitudinal pilot study examining health determinants of cardiac outcomes 12 months post percutaneous coronary intervention

Background Percutaneous coronary intervention (PCI) is a very common revascularisation procedure for coronary artery disease (CAD). The purpose of this study was to evaluate cardiac outcomes, health related quality of life (HRQoL), resilience and adherence behaviours in patients who have undergone a PCI at two time points (6 and 12 months) following their procedure. Methods A longitudinal pilot study was conducted to observe the cardiac outcomes across a cohort of patients who had undergone a percutaneous coronary intervention (PCI). Participants who had undergone PCI 6 months prior were invited. Those participants who met the inclusion criteria and provided consent then completed a telephone survey (time point 1). These participants were then contacted 6 months later (i.e. 12 months post-intervention, time point 2) and the measures were repeated. Results All patients (n = 51) were recorded as being alive at time point 1. The multiple model indicated that controlling for other factors, gender was significantly associated with a linear combination of outcome measures (p = 0.004). The effect was moderate in magnitude (partial-η2 = 0.303), where males performed significantly better than females 6 months after the PCI procedure physically and with mood. Follow-up univariate ANOVAs indicated that gender differences were grounded in the scale measuring depression (PHQ9) (p = 0.005) and the physical component score of the short form measuring HRQoL (SF12-PCS) (p = 0.003). Thirteen patients were lost to follow-up between time points 1 and 2. One patient was confirmed to have passed away. The pattern of correlations between outcome measures at time point 2 revealed statistically significant negative correlation between the PHQ instrument and the resilience scale (CD-RISC) (r = -0.611; p < 0.001); and the physical component score of the SF-12 instrument (r = -0.437; p = 0.054). Conclusions Men were performing better than women in the 6 months post-PCI, particularly in the areas of mood (depression) and physical health. This pilot results indicate gender-sensitive practices are recommended particularly up to 6 months post-PCI. Any gender differences observed at 6 month appear to disappear at 12 months post-PCI. Further research into the management of mood particularly for women post-PCI is warranted. A more detailed inquiry related to access/attendance to secondary prevention is also warranted

Sociodemographic determinants of oral anticoagulant prescription in patients with atrial fibrillations: Findings from the PINNACLE registry using machine learning

Background: Current risk scores that are solely based on clinical factors have shown modest predictive ability for understanding of factors associated with gaps in real-world prescription of oral anticoagulation (OAC) in patients with atrial fibrillation (AF).Objective: In this study, we sought to identify the role of social and geographic determinants, beyond clinical factors associated with variation in OAC prescriptions using a large national registry of ambulatory patients with AF.Methods: Between January 2017 and June 2018, we identified patients with AF from the American College of Cardiology PINNACLE (Practice Innovation and Clinical Excellence) Registry. We examined associations between patient and site-of-care factors and prescription of OAC across U.S. counties. Several machine learning (ML) methods were used to identify factors associated with OAC prescription.Results: Among 864,339 patients with AF, 586,560 (68%) were prescribed OAC. County OAC prescription rates ranged from 26.8% to 93%, with higher OAC use in the Western United States. Supervised ML analysis in predicting likelihood of OAC prescriptions and identified a rank order of patient features associated with OAC prescription. In the ML models, in addition to clinical factors, medication use (aspirin, antihypertensives, antiarrhythmic agents, lipid modifying agents), and age, household income, clinic size, and U.S. region were among the most important predictors of an OAC prescription.Conclusion: In a contemporary, national cohort of patients with AF underuse of OAC remains high, with notable geographic variation. Our results demonstrated the role of several important demographic and socioeconomic factors in underutilization of OAC in patients with AF

Impaired Chronotropic Response to Exercise Stress Testing in Patients With Diabetes Predicts Future Cardiovascular Events

OBJECTIVES— To assess the association between impaired chronotropic response (CR) and adverse events among patients with diabetes referred for exercise treadmill testing (ETT)

Clinical Prediction Model Suitable for Assessing Hospital Quality for Patients Undergoing Carotid Endarterectomy

Background: Assessing hospital quality in the performance of carotid endarterectomy (CEA) requires appropriate risk adjustment across hospitals with varying case mixes. The aim of this study was to develop and validate a prediction model to assess the risk of in‐hospital stroke or death after CEA that could aid in the assessment of hospital quality. Methods and Results: Patients from National Cardiovascular Data Registry (NCDR)'s Carotid Artery Revascularization and Endarterectomy (CARE) Registry undergoing CEA without acute evolving stroke from 2005 to 2013 were included. In‐hospital stroke or death was modeled using hierarchical logistic regression with 20 candidate variables and accounting for hospital‐level clustering. Internal validation was achieved with bootstrapping; model discrimination and calibration were assessed. A total of 213 (1.7%) primary end point events occurred during 12 889 procedures. Independent predictors of stroke or death included age, prior peripheral artery disease, diabetes mellitus, prior coronary artery disease, having a symptomatic carotid lesion, having a contralateral carotid occlusion, or having New York Heart Association Class III or IV heart failure. The model was well calibrated and demonstrated moderate discriminative ability (c‐statistic 0.65). The NCDR CEA score was then developed to support simple, prospective risk quantification in the clinical setting. Conclusions: The NCDR CEA score, comprising 7 clinical variables, predicts in‐hospital stroke or death after CEA. This model can be used to estimate hospital risk‐adjusted outcomes for CEA and to assist with the assessment of hospital quality

Cardiac Performance Measure Compliance in Outpatients The American College of Cardiology and National Cardiovascular Data Registry's PINNACLE (Practice Innovation And Clinical Excellence) Program

ObjectivesWe examined compliance with performance measures for 14,464 patients enrolled from July 2008 through June 2009 into the American College of Cardiology's PINNACLE (Practice Innovation And Clinical Excellence) program to provide initial insights into the quality of outpatient cardiac care.BackgroundLittle is known about the quality of care of outpatients with coronary artery disease (CAD), heart failure, and atrial fibrillation, and whether sex and racial disparities exist in the treatment of outpatients.MethodsThe PINNACLE program is the first, national, prospective office-based quality improvement program of cardiac patients designed, in part, to capture, report, and improve outpatient performance measure compliance. We examined the proportion of patients whose care was compliant with established American College of Cardiology, American Heart Association, and American Medical Association-Physician Consortium for Performance Improvement (ACC/AHA/PCPI) performance measures for CAD, heart failure, and atrial fibrillation.ResultsThere were 14,464 unique patients enrolled from 27 U.S. practices, accounting for 18,021 clinical visits. Of these, 8,132 (56.4%) had CAD, 5,012 (34.7%) had heart failure, and 2,786 (19.3%) had nonvalvular atrial fibrillation. Data from the PINNACLE program were feasibly collected for 24 of 25 ACC/AHA/PCPI performance measures. Compliance with performance measures ranged from being very low (e.g., 13.3% of CAD patients screened for diabetes mellitus) to very high (e.g., 96.7% of heart failure patients with blood pressure assessments), with moderate (70% to 90%) compliance observed for most performance measures. For 3 performance measures, there were small differences in compliance rates by race or sex.ConclusionsFor more than 14,000 patients enrolled from 27 practices in the outpatient PINNACLE program, we found that compliance with performance measures was variable, even after accounting for exclusion criteria, suggesting an important opportunity to improve the quality of outpatient care

Cardiovascular health:The importance of measuring patient-reported health status

A scientific statement from the American Heart Association Keywords: cardiovascular diseases; health care evaluation mechanisms; health status; health surveys; patient

Percutaneous Coronary Intervention and Drug-Eluting Stent Use Among Patients ≥85 Years of Age in the United States

ObjectivesThis study assessed the comparative effectiveness of drug-eluting stents (DES) versus bare-metal stents (BMS) among patients ≥85 years of age.BackgroundDespite an aging population, little is known about the comparative effectiveness of DES versus BMS among patients age ≥85 years undergoing percutaneous coronary intervention (PCI).MethodsWe examined 471,006 PCI patients age ≥65 years at 947 hospitals in the National Cardiovascular Data Registry between 2004 and 2008 and linked to Medicare claims data. Long-term outcomes (median follow-up 640.8 ± 423.5 days) were compared between users of DES and BMS.ResultsPatients age ≥85 years comprise an increasing proportion of PCIs performed among elderly subjects, yet rates of DES use declined the most in this age group. Compared with BMS, use of DES was associated with lower mortality: age ≥85 years, 29% versus 38% (adjusted hazard ratio [HR]: 0.80 [95% confidence interval (CI): 0.77 to 0.83]); age 75 to 84 years, 17% versus 25% (HR: 0.77 [95% CI: 0.75 to 0.79]); and age 65 to 74 years, 10% versus 16% (HR: 0.73 [95% CI: 0.71 to 0.75]). However, the adjusted mortality difference narrowed with increasing age (pinteraction <0.001). In contrast, the adjusted HR for myocardial infarction rehospitalization associated with DES use was significantly lower with increasing age: age ≥85 years, 9% versus 12% (HR: 0.77 [95% CI: 0.71 to 0.83]); age 75 to 84 years, 7% versus 9% (HR: 0.81 [95% CI: 0.77 to 0.84]); and age 65 to 74 years, 7% versus 8% (HR: 0.84 [95% CI: 0.80 to 0.88]) (pinteraction <0.001).ConclusionsIn this national study of older patients undergoing PCI, declines in DES use were most pronounced among those aged ≥85 years, yet lower adverse-event rates associated with DES versus BMS use were observed

Risk of cardiovascular and all-cause mortality: impact of impaired health-related functioning and diabetes: the Australian Diabetes, Obesity and Lifestyle (AusDiab) study.

OBJECTIVE: There is an established link between health-related functioning (HRF) and cardiovascular disease (CVD) mortality, and it is known that those with diabetes predominantly die of CVD. However, few studies have determined the combined impact of diabetes and impaired HRF on CVD mortality. We investigated whether this combination carries a higher CVD risk than either component alone. RESEARCH DESIGN AND METHODS: The Australian Diabetes, Obesity and Lifestyle (AusDiab) study included 11,247 adults aged ≥ 25 years from 42 randomly selected areas of Australia. At baseline (1999-2000), diabetes status was defined using the World Health Organization criteria and HRF was assessed using the SF-36 questionnaire. RESULTS: Overall, after 7.4 years of follow-up, 57 persons with diabetes and 105 without diabetes had died from CVD. In individuals with and without diabetes, HRF measures were significant predictors of increased CVD mortality. The CVD mortality risks among those with diabetes or impaired physical health component summary (PCS) alone were similar (diabetes only: hazard ratio 1.4 [95% CI 0.7-2.7]; impaired PCS alone: 1.5 [1.0-2.4]), while those with both diabetes and impaired PCS had a much higher CVD mortality (2.8 [1.6-4.7]) compared with those without diabetes and normal PCS (after adjustment for multiple covariates). Similar results were found for the mental health component summary. CONCLUSIONS: This study demonstrates that the combination of diabetes and impaired HRF is associated with substantially higher CVD mortality. This suggests that, among those with diabetes, impaired HRF is likely to be important in the identification of individuals at increased risk of CVD mortality

Patient-rated health status predicts prognosis following percutaneous coronary intervention with drug-eluting stenting

Purpose: In patients treated with percutaneous coronary intervention (PCI) with the paclitaxel-eluting stent, we examined whether patient-rated health status predicts adverse clinical events. Methods: Consecutive PCI patients treated with drug-eluting stenting (N = 870; 72.2% men; mean age = 62.6 ± 11.5) completed the EQ-5D post-PCI. The EQ-5D levels were dichotomized into 'no problems' (level 1) versus 'problems' (levels 2, 3); the visual analogue scale (VAS) was dichotomized using the 25th percentile (cut-off ≤60) indicating poor health status. Patients were followed up for 1-year clinical events (death or non-fatal myocardial infarction (MI)). Results: There were 53 deaths/MIs at follow-up. The EQ-5D health status dimensions mobility (HR:2.23; 95% CI:1.25-3.97), self-care (HR:3.09; 95% CI:1.54-6.20), and self-reported health status as measured with the EQ-VAS (HR:2.94; 95% CI:1.65-5.25) were independent predictors of death/MI and added to the predictive value of a model comprised of demographic and clinical characteristics. The EQ-5D dimensions usual activities, pain/discomfort, and anxiety/depression were not associated with adverse clinical events in adjusted analysis. Conclusions: Patient-rated health status predicted adverse clinical events at 1-year follow-up in PCI patients treated with drug-eluting stenting, with the risk being more than 2-fold indepe