Geographic Variation in Cardioprotective Antihypertensive Medication Usage in Dialysis Patients

Department of Medicine, Division of Nephrology and Hypertension, University of Kansas School of Medicine, Kansas City, KS 66160, USA.
American Journal of Kidney Diseases (Impact Factor: 5.9). 07/2011; 58(1):73-83. DOI: 10.1053/j.ajkd.2011.02.387
Source: PubMed


Despite their high risk of adverse cardiac outcomes, persons on long-term dialysis therapy have had lower use of antihypertensive medications with cardioprotective properties, such as angiotensin-converting enzyme (ACE) inhibitors/angiotensin receptor blockers (ARBs), β-blockers, and calcium channel blockers, than might be expected. We constructed a novel database that permits detailed exploration into the demographic, clinical, and geographic factors associated with the use of these agents in hypertensive long-term dialysis patients.
National cross-sectional retrospective analysis linking Medicaid prescription drug claims with US Renal Data System core data.
48,882 hypertensive long-term dialysis patients who were dually eligible for Medicaid and Medicare services in 2005.
Demographics, comorbid conditions, functional status, and state of residence.
Prevalence of cardioprotective antihypertensive agents in Medicaid pharmacy claims and state-specific observed to expected ORs of medication exposure.
Factors associated with medication use were modeled using multilevel logistic regression models.
In multivariable analyses, cardioprotective antihypertensive medication exposure was associated significantly with younger age, female sex, nonwhite race, intact functional status, and use of in-center hemodialysis. Diabetes was associated with a statistically significant 28% higher odds of ACE-inhibitor/ARB use, but congestive heart failure was associated with only a 9% increase in the odds of β-blocker use and no increase in ACE-inhibitor/ARB use. There was substantial state-by-state variation in the use of all classes of agents, with a greater than 2.9-fold difference in adjusted-rate ORs between the highest and lowest prescribing states for ACE inhibitors/ARBs and a 3.6-fold difference for β-blockers.
Limited generalizability beyond study population.
In publicly insured long-term dialysis patients with hypertension, there were marked differences in use rates by state, potentially due in part to differences in Medicaid benefits. However, geographic characteristics also were associated with exposure, suggesting clinical uncertainty about the utility of these medications.

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Available from: Purna Mukhopadhyay, Apr 15, 2014
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    • "Many other aspects of dialysis care demonstrate regional variability. For example, recent studies have shown marked variation in cardioprotective medication prescription [42,43] and kidney transplanatation [44,45] across geographic regions in the United States that cannot be explained by patient demographics or burden of comorbidities. "
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    ABSTRACT: 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. 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. 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. 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.
    BMC Nephrology 02/2014; 15(1):40. DOI:10.1186/1471-2369-15-40 · 1.69 Impact Factor
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    • "Our study has several strengths. First, data were obtained from the third-largest dialysis provider in the US, allowing us to evaluate differences in BP medication prescriptions between hemodialysis and peritoneal dialysis patients and to stratify our analyses by several characteristics, including baseline CHF, CVD, and diabetes, which influence prescription of cardioprotective medications [14]. Second, our analysis provides in-depth examination of contemporary prescribing patterns, which is important because BP medication prescription is influenced by available evidence on efficacy and by generic availability. "
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    ABSTRACT: Several observational studies have evaluated the effect of a single exposure window with blood pressure (BP) medications on outcomes in incident dialysis patients, but whether BP medication prescription patterns remain stable or a single exposure window design is adequate to evaluate effect on outcomes is unclear. We described patterns of BP medication prescription over 6 months after dialysis initiation in hemodialysis and peritoneal dialysis patients, stratified by cardiovascular comorbidity, diabetes, and other patient characteristics. The cohort included 13,072 adult patients (12,159 hemodialysis, 913 peritoneal dialysis) who initiated dialysis in Dialysis Clinic, Inc., facilities January 1, 2003-June 30, 2008, and remained on the original modality for at least 6 months. We evaluated monthly patterns in BP medication prescription over 6 months and at 12 and 24 months after initiation. Prescription patterns varied by dialysis modality over the first 6 months; substantial proportions of patients with prescriptions for beta-blockers, renin angiotensin system agents, and dihydropyridine calcium channel blockers in month 6 no longer had prescriptions for these medications by month 24. Prescription of specific medication classes varied by comorbidity, race/ethnicity, and age, but little by sex. The mean number of medications was 2.5 at month 6 in hemodialysis and peritoneal dialysis cohorts. This study evaluates BP medication patterns in both hemodialysis and peritoneal dialysis patients over the first 6 months of dialysis. Our findings highlight the challenges of assessing comparative effectiveness of a single BP medication class in dialysis patients. Longitudinal designs should be used to account for changes in BP medication management over time, and designs that incorporate common combinations should be considered.
    BMC Nephrology 11/2013; 14(1):249. DOI:10.1186/1471-2369-14-249 · 1.69 Impact Factor
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    ABSTRACT: Geographic variation in the occurrence and outcomes of chronic kidney disease (CKD) is major area of study in epidemiology and health services and outcomes research. Geographic attributes may be as diverse as the physical, socioeconomic, and medical care characteristics of an environment. This review summarizes the recent literature pertaining to geographic risk factors and CKD. Studies have reported on the association between CKD and physical attributes of place (ambient temperature and altitude), the impact of disasters on CKD populations, new diseases characterized by regional localization, national variations in CKD incidence and prevalence, regional variation in end-stage renal disease incidence, residential mobility and CKD risk factors, and geographic variations in CKD care. The emerging role of tools for geospatial studies - including multilevel analytical designs, which reduce the likelihood of an ecologically biased inference, and geographic information systems, which allow the simultaneous linkage, analysis, and mapping of geospatial data - is illustrated by these studies. Our understanding of the occurrence and outcomes of CKD will continue to be expanded and deepened by the explicit study of attributes associated with place as a potential risk factor. Many of the studies reviewed are largely hypothesis generating, and a better understanding of the role of geography in the study of CKD awaits investigations that probe the mechanisms that link attributes of place to disease processes.
    Current opinion in nephrology and hypertension 03/2012; 21(3):323-8. DOI:10.1097/MNH.0b013e3283521dae · 3.96 Impact Factor
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