Conceptualizing multiple drug use in patients with comorbidity and multimorbidity: proposal for standard definitions beyond the term polypharmacy

Abstract

With older and ageing populations, patients experience multiple chronic diseases at the same time. Individual chronic disease guidelines often recommend pharmacological therapies as a key intervention, resulting in patients being prescribed multiple regular medications for their different diseases. Whilst the term 'polypharmacy' has been applied to the use of multiple medications, there is no consistent definition and this term is now being used all inclusively. To improve both scientific rigor and optimal patient care, it is crucial that a standard terminology is used which reclassifies the term 'polypharmacy' into distinct phenotypes relating to the index chronic disease, additional conditions to the index ('comorbidity') or the experience of multiple chronic conditions at the same time (multimorbidity). Using three exemplar index conditions; heart failure, type 2 diabetes and breast cancer, we propose the reclassification of the term 'polypharmacy' into three distinct phenotypes. First, index drug or multi-index drug therapy, where each index condition creates multiple drug use for that condition; second, co-drug therapy, where addition of other comorbid conditions increases the multiple drug use and may influence the management of the index disease and third, multi drug therapy, where adult population with multimorbidity may be on many drugs. This paper reviews guidelines for the individual exemplars to develop the basis for the new terms and then develops the pharmaco-epidemiology of multiple drug use further by reviewing the evidence on the relationship between the phenotypic classification and important outcomes. The importance of standardising 'polypharmacy' terminology for the scientific agenda and clinical practice is that it relates to an index condition or disease safety outcomes including drug interactions, adverse side effects in hospital admissions and related 'polypill' concept.

<p>Failure to Reach a Consensus in Polypharmacy Definition: An Obstacle to Measuring Risks and Impacts—Results of a Literature Review</p>

“…Others are trying to define relevant indicators to move towards a precise measurement of polypharmacy whether comparing the ability of indicators to identify polypharmacy and evaluating the technical feasibility of their calculations, 8 proposing alternative terminologies 15 or, much more recently, establishing a standard definition of the term "polypharmacy" based on an index including the many parameters associated with comorbidity and multi-morbidity. 42 Research on polypharmacy is moving towards an increasingly holistic approach. Polypharmacy could be defined, therefore, within the intersection between its many etiological or risk factors (health status, general frailty, comorbid conditions, certain diagnoses, prescribing cascades, self-medication, inappropriate prescription, etc.…”

The influence of integrated geriatric outpatient clinics on the health care utilization of older people

“…The definition of polypharmacy is variable. In general, polypharmacy refers to excessive unnecessary drug consumption or the use of high numbers of drugs and is a convenient evaluation method to use in practice [7,8]. Older adults using more than 8 drugs have increased risks of rehospitalization [9].…”

Potential Drug-Drug Interactions in Heart Failure Patients

“…A total of 199 out of the 239 selected patients (83.3 %) in the study were elderly, and 98 % of them received more than 5 drugs (polypharmacy) and thus gave us the reason to assign these patients as high-risk patients in terms of hazardous pDDIs and their therapy needed higher alertness [3,6,12]. In addition, 36.1 percent of patients had chronic kidney disease and 9.5 percent were with chronic renal failure, another contributing factor to the increased risk of pDDIs.…”