Patterns of medication use in the RRI-CKD study: focus on medications with cardiovascular effects

Patients with chronic kidney disease (CKD) stages 2-5 are known to suffer numerous complications and co-morbidities associated with kidney disease. The medication prescription patterns in this population are not well understood. We report on prescription data collected as part of a multicentre longitudinal study in patients with CKD, with a focus on medications with cardiovascular or cardioprotective effects.

Patients were recruited from four academic nephrology centres in the USA, with patient recruitment from June 2000 to March 2002. Medication data were captured at the time of first enrollment into the study. Individual medications were classified into medication groups, and those with predominant cardioprotective effects or for prevention of progression of kidney disease (e.g. medications for treatment of anaemia, lipid-lowering agents, antihypertensives, statins, etc.) were recorded for analysis. Descriptive statistics were used for medication prescription according to baseline demographics and co-morbidities. Predictors of epoetin and iron use were determined by logistic regression adjusting for age, race, sex, diabetes, glomerular filtration rate (GFR), haemoglobin and serum albumin.

Medication data were available for 619 patients with stages 2-5 CKD. Patients were 60.6+/-16.0 years of age, and were prescribed 8+/-4 (range 1-28) medications. Overall, the proportion of patients prescribed different classes of medications included epoetin (20%), intravenous iron (13%), HMG-CoA reductase inhibitors (16%), angiotensin-converting enzyme (ACE) inhibitors (44%), angiotensin receptor blockers (13%), beta-blockers (46%), calcium channel blockers (52%) and aspirin (37%). There was a low use of epoetin (45%) and iron (20%) in patients with anaemia. Only 24% of patients with coronary artery disease were prescribed statins, and ACE inhibitors and angiotensin receptor blockers were used in only 58 and 23% of diabetic patients with proteinuria. Positive predictors of epoetin and iron therapy included white race and diabetes. Higher GFR and higher serum albumin were associated with lower odds of being prescribed epoetin. White race and diabetics were more likely to be prescribed iron.

This study provides an overview of prescription practices in a cohort of CKD patients. Substantial underutilization of certain classes of cardioprotective medications is apparent, and systematic educational efforts in this direction may well prove worthwhile to impact outcomes.