Geographic variation in HMG-CoA reductase inhibitor use in dialysis patients

Geographic Variation of Statin Use Among US Nursing Home Residents With Life-limiting Illness

BACKGROUND

Medically compromised nursing home residents continue to be prescribed statins, despite questionable benefits.

OBJECTIVE

To describe regional variation in statin use among residents with life-limiting illness.

RESEARCH DESIGN

Cross-sectional study using 2016 Minimum Data Set 3.0 assessments linked to Medicare administrative data and health service utilization area resource files.

SETTING

Nursing homes (n=14,147) within hospital referral regions (n=306) across the United States.

SUBJECTS

Long-stay residents (aged 65 y and older) with life-limiting illness (eg, serious illness, palliative care, or prognosis <6 mo to live) (n=361,170).

MEASURES

Prevalent statin use was determined by Medicare Part D claims. Stratified by age (65-75, 76 y or older), multilevel logistic models provided odds ratios with 95% confidence intervals.

RESULTS

Statin use was prevalent (age 65-75 y: 46.0%, 76 y or more: 31.6%). For both age groups, nearly all resident-level variables evaluated were associated with any and high-intensity statin use and 3 facility-level variables (ie, higher proportions of Black residents, skilled nursing care provided, and average number of medications per resident) were associated with increased odds of statin use. Although in residents aged 65-75 years, no associations were observed, residents aged 76 years or older located in hospital referral regions (HRRs) with the highest health care utilization had higher odds of statin use than those in nursing homes in HRRs with the lowest health care utilization.

CONCLUSIONS

Our findings suggest extensive geographic variation in US statin prescribing across HRRs, especially for those aged 76 years or older. This variation may reflect clinical uncertainty given the largely absent guidelines for statin use in nursing home residents.

Risk Factors for Suboptimal Utilization of Statins and Antiplatelet Therapy in Patients Undergoing Revascularization for Symptomatic Peripheral Arterial Disease

BACKGROUND

The objective of this study was to identify risk factors for suboptimal medical therapy (defined as reported antiplatelet and statin use) among patients undergoing lower extremity bypass (LEB) and peripheral vascular interventions (PVIs) for symptomatic peripheral arterial disease (PAD).

METHODS

The Vascular Study Group of Greater New York (VSGGNY) database was used to identify all patients undergoing PVI or LEB for PAD (2011-2013). Bivariate analyses were performed to identify characteristics of patients who were not prescribed statins and/or antiplatelet agents before revascularization. Multivariate relative risk regression models were developed to identify patients at risk for suboptimal therapy, with regards to antiplatelet and statin therapy.

RESULTS

About 1,030 patients underwent endovascular therapy (n = 822; 80%) or surgical bypass (n = 208; 20%) for symptomatic PAD (57.2% claudication; 15% rest pain and 27.8% tissue loss). Overall, preoperative statin use was observed in 59%. Preoperative antiplatelet therapy was observed in 79% of patients. Bivariate analysis revealed comparatively reduced statin use among patients without other cardiovascular risk factors including hypertension (63% vs. 39.3%; P < 0.0001) and coronary artery disease (CAD) with or without prior cardiac revascularization (coronary artery bypass grafting [CABG]/percutaneous coronary intervention [PCI]; 75.2% vs. 47.4%; P < 0.0001). Multivariate relative risk regression confirmed higher rates of statin use among patients with other cardiovascular risk factors including hypertension (1.14 [1.02-1.27]; P = 0.02) and CAD with prior CABG/PCI (1.22 [1.13-1.31]; P < 0.0001). Reduced statin use was observed in patients over 80 years old. (0.92 [0.84-0.1.0]; P = 0.059). By multivariate regression, antiplatelet therapy use was associated with CAD and/or prior CABG/PCI (1.11 [1.04-1.17]; P = 0.0015) and prior peripheral revascularization (1.07 [1.01-1.13]; P = 0.03).

CONCLUSIONS

Patients with symptomatic PAD, but without an antecedent cardiovascular history, are less likely to be optimally managed with statins and antiplatelet therapy preoperatively. Given the established role of these medications in the optimal medical management of patients with PAD, this presents an opportunity for improvement in the overall vascular care of patients undergoing intervention for symptomatic PAD at VSGGNY centers.

Association between higher rates of cardioprotective drug use and survival in patients on dialysis

BACKGROUND

While cardiovascular (CV) disease is a leading cause of morbidity and mortality in patients on chronic dialysis, utilization rates of cardioprotective drugs for dialysis patients remain low. This study sought to determine whether higher rates of cardioprotective drug use among dialysis patients might increase survival.

METHODS

A retrospective cohort of incident dialysis patients (n = 50,468) with dual eligibility for U.S. Medicare and Medicaid was constructed using USRDS data linked with billing claims. Medication exposures included angiotensin converting enzyme inhibitors/angiotensin receptor blockers (ACEIs/ARBs), β-blockers, calcium channel blockers (CCBs), and HMG-CoA reductase inhibitors (statins) prescribed within 90 days of dialysis initiation. The outcomes were one- and two-year survival and CV event-free survival. Variation in treatment rates based on local area practice styles were used as instruments in instrumental variable (IV) estimation, yielding average treatment effect estimates for patients whose treatment choices were affected by local area practice styles.

RESULTS

Patients aged 65 years and older comprised 47.4% of the sample, while 59.5% were female and 35.0% were white. The utilization rate was 40.7% for ACEIs/ARBs, 43.0% for β-blockers, 50.7% for CCBs and 26.4% for statins. The local area practice style instruments were highly significantly related to cardioprotective drug use in dialysis patients (Chow-F values > 10). IV estimates showed only that higher rates of β-blockers increased one-year survival (β = 0.161, P-value = 0.020) and CV event-free survival (β = 0.189, P-value = 0.033), but that higher rates of CCBs decreased two-year CV event-free survival (β = -0.520, P-value = 0.009).

CONCLUSIONS

This study suggests that higher utilization rates of β-blockers might yield higher survival rates for dialysis patients. However, higher rates of the other drugs studied had no correlations with survival, and higher CCB rates might actually reduce CV-event free survival. Since the benefits of cardioprotective drugs may vary across dialysis patients, the study findings should be interpreted only with respect to changes of utilization rates around the rates observed in this study.

The association between geographic proximity to a dialysis facility and use of dialysis catheters

BACKGROUND

Residing remotely from health care resources appears to impact quality of care delivery. It remains unclear if there are differences in vascular access based on distance of one's residence to dialysis centre at time of dialysis initiation, and whether region or duration of pre-dialysis care are important effect modifiers.

METHODS

We studied the association of distance from a patients' residence to the nearest dialysis centre and central venous catheter (CVC) use in an observational study of 26,449 incident adult dialysis patients registered in the Canadian Organ Replacement Registry between 2000-2009. Multivariate logistic regression was used to assess the association between distance in tertiles and CVC use, adjusted for patient demographics and comorbidities. Geographic region and duration of pre-dialysis care were examined as potential effect modifiers.

RESULTS

Eighty percent of patients commenced dialysis with a CVC. Incident CVC use was highest among those living > 20 km from the dialysis centre (OR 1.29 (1.24-1.34)) compared to those living < 5 km from centre. The length of pre-dialysis care and geographic region were significant effect modifiers; among patients residing in the furthest tertile (>20 km) from the nearest dialysis centre, incident CVC use was more common with shorter length of pre-dialysis care (< 1 year) and residence in central regions of the country.

CONCLUSION

Residing further from a dialysis centre is associated with increased CVC use, an effect modified by shorter pre-dialysis care and the geographic region of the country. Efforts to reduce geographical disparities in pre dialysis care may decrease CVC use.