Prevalence of renally inappropriate medicines in older people with renal impairment - A cross-sectional register-based study in a large primary care population.

The aim of this population-based, cross-sectional study was to analyse the prevalence of renally inappropriate medicines (RIMs) in older people with renal impairment. We included 30 372 people aged ≥65 years with chronic kidney disease (CKD) stage 3, and 2161 with stage 4 attending primary care in Stockholm, Sweden. We used data derived from SCREAM, a database linking patient-specific data on demography, morbidity, healthcare consumption and dispensed drugs to creatinine measurements. Estimated glomerular filtration rate was calculated with CKD-EPI based on the first non-hospital serum creatinine in 2010. RIMs were defined as medicines needing dose adjustment or being contra-indicated in CKD stage 3 or 4 with reference to Swedish "Janusmed Drugs and Renal function." Dispensed prescription drugs were analysed during 1 year after creatinine assessment. Drug doses were considered as excessive if their mean volume dispensed per day exceeded the recommended dose. Contra-indicated medicines were regarded as inappropriate if dispensed at least once during 1 year. Excessive dosing was present in 42.5% of older people with CKD stage 3 and in 58.1% with stage 4. The prevalence of contra-indicated medicines was 9.4% and 38.0%, respectively. A limited number of RIMs accounted for the majority of excessive dosing, such as drugs acting on the renin-angiotensin-aldosterone system, betablockers and opioids. Commonly dispensed contra-indicated substances were NSAIDs and antidiabetics. We conclude that the prevalence of RIMs in older people with renal impairment is considerably high. Still, RIM use may be manageable as only a limited number of RIMs are frequently used.