Risk factors for potentially inappropriate prescribing to older patients in primary care.

PURPOSE: The aim of this study is to determine modifiable risk factors contributing to potentially inappropriate prescribing in older primary care outpatients (≥65 years).

METHODS: Two separate, age- and sex-matched case-control studies were carried out simultaneously at the Primary Health Care Center Kragujevac, Serbia, during the period September 2013-September 2014. The cases were defined as patients with at least one prescription for potentially inappropriate medication (PIM) according to Screening Tool of Older Persons potentially inappropriate Prescriptions (STOPP) criteria (n = 122), and patients who had at least one potential prescribing omission (PPO) listed in Screening Tool to Alert doctors to the Right Treatment (START) criteria (n = 108), while the control groups consisted of patients without such outcomes (n = 244 and n = 216, respectively).

RESULTS: A total of 138 PIM and 161 PPO events were identified using 26 (41.3 %) of STOPP criteria and 17 (77.3 %) of START indicators, respectively. The unhealthy behaviors including at least two of the following: sedentary lifestyle, improper nutrition, active smoking or heavy alcohol consumption (adjusted OR 2.57, 95 % CI 1.28-5.20), use of multiple drugs (five to eight drugs, adjusted OR 3.05, 95 % CI 1.59-5.85; ≥9 of drugs adjusted OR 7.17, 95 % CI 3.07-16.74) and frequent contacts between patients chosen general practitioners (GPs) and pharmaceutical sales representatives (adjusted OR 2.28, 95 % CI 1.10-4.75), were identified as major risk factors for PIM use. Patients who were handled by GPs from smaller practices (adjusted OR 0.51, 95 % CI 0.29-0.93), those with more organ systems affected by the extremely severe disorders and those who often visited the outpatient specialist services (adjusted OR 0.88, 95 % CI 0.81-0.95), had a significantly reduced risk of PPO.

CONCLUSIONS: This study suggests that avoidance of major polypharmacy, use of nonpharmacological measures to improve lifestyle habits and decreasing the exposure of physicians to drug promotional material may reduce the risk of PIM use in older primary care outpatients. The only modifiable protective factors for PPOs were working environment of the patients chosen GPs and more frequent ambulatory visits to specialists.