Polypharmacy: A general review of definitions, descriptions and determinants.

Polypharmacy is considered as the administration of many drugs. It is a major public health concern, which is growing worldwide. The identification of polypharmacy relies on drug count on a given time window. Polypharmacy exists if this count exceeds a predefined threshold. Although there is no consensus among scientists, five is the most frequently used number. Depending on the time-windows, polypharmacy can be qualified as simultaneous, cumulative, or continuous. Drugs can be selected according to the duration or the recurrence of their use thereby introducing the concept of chronic polypharmacy. This general review aimed to compile data from the literature regarding descriptions and determinants of polypharmacy, according to used definitions and studied populations. The prevalence of polypharmacy varied according to the definition used (from 4% to 57%). It was high in elderly people but was also non negligible in younger subjects such as middle aged. Cardiovascular, digestive and metabolism drugs were among the most frequent drugs involved in polypharmacy. The determinants of polypharmacy included factors linked to the patient (sociodemographic parameters such as age, sex, income, and place of residence, ethnicity, behaviour), factors linked to the disease (certain diseases such as cardiovascular or metabolic disease, multiple comorbidity status), as well as factors linked to the healthcare system or to the physician. Finally, to date, little data is available regarding polypharmacy appropriateness, although these data are needed to have clinically important information beyond a quantitative estimation. Further research is warranted to fill this gap.