Multimorbidity and the associated use of multiple medicines (polypharmacy), is common in the older population. Despite this, there is no consensus definition for polypharmacy. A systematic review was conducted to identify and summarise polypharmacy definitions in existing literature. The reporting of this systematic review conforms to the Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) checklist. MEDLINE (Ovid), EMBASE and Cochrane were systematically searched, as well as grey literature, to identify articles which defined the term polypharmacy (without any limits on the types of definitions) and were in English, published between 1st January 2000 and 30th May 2016. Definitions were categorised as i. numerical only (using the number of medications to define polypharmacy), ii. numerical with an associated duration of therapy or healthcare setting (such as during hospital stay) or iii. Descriptive (using a brief description to define polypharmacy). A total of 1156 articles were identified and 110 articles met the inclusion criteria. Articles not only defined polypharmacy but associated terms such as minor and major polypharmacy. As a result, a total of 138 definitions of polypharmacy and associated terms were obtained. There were 111 numerical only definitions (80.4% of all definitions), 15 numerical definitions which incorporated a duration of therapy or healthcare setting (10.9%) and 12 descriptive definitions (8.7%). The most commonly reported definition of polypharmacy was the numerical definition of five or more medications daily (n = 51, 46.4% of articles), with definitions ranging from two or more to 11 or more medicines. Only 6.4% of articles classified the distinction between appropriate and inappropriate polypharmacy, using descriptive definitions to make this distinction. Polypharmacy definitions were variable. Numerical definitions of polypharmacy did not account for specific comorbidities present and make it difficult to assess safety and appropriateness of therapy in the clinical setting.

Objectives To provide a map of Anatomical Therapeutic Chemical (ATC) Classification System codes to individual Rx-Risk comorbidities and to validate the Rx-Risk Comorbidity Index. Design The 46 comorbidities in the Rx-Risk Index were mapped to dispensing’s indicative of each condition using ATC codes. Prescription dispensing claims in 2014 were used to calculate the Rx-Risk. A baseline logistic regression model was fitted using age and gender as covariates. Rx-Risk was added to the base model as an (1) unweighted score, (2) weighted score and as (3) individual comorbidity categories indicating the presence or absence of each condition. The Akaike information criterion and c-statistic were used to compare the models. Setting Models were developed in the Australian Government Department of Veterans’ Affairs health claims data, and external validation was undertaken in a 10% sample of the Australian Pharmaceutical Benefits Scheme Data. Participants Subjects aged 65 years or older. Outcome measures Death within 1 year (eg, 2015). Results Compared with the base model (c-statistic 0.738, 95% CI 0.734 to 0.742), including Rx-Risk improved prediction of mortality; unweighted score 0.751, 95% CI 0.747 to 0.754, weighted score 0.786, 95% CI 0.782 to 0.789 and individual comorbidities 0.791, 95% CI 0.788 to 0.795. External validation confirmed the utility of the weighted index (c-statistic=0.833). Conclusions The updated Rx-Risk Comorbidity Score was predictive of 1-year mortality and may be useful in practice to adjust for confounding in observational studies using medication claims data.

Medications are frequently reported as both predisposing factors and inducers of delirium. This review evaluated the available evidence and determined the magnitude of risk of postoperative delirium associated with preoperative medication use. A systematic search in Medline and EMBASE was conducted using MeSH terms and keywords for postoperative delirium and medication. Studies which included patients 18 years and older who underwent major surgery were included. The methodological quality of included studies was assessed independently by two authors using the Newcastle-Ottawa quality assessment scale for cohort studies. Twenty-nine studies; 25 prospective cohort, three retrospective cohort and one post hoc analysis of RCT data were included. Only four specifically aimed to assess medicines as an independent predictor of delirium, all other studies included medicines among a number of potential predictors of delirium. Of the studies specifically testing the association with a medication class, preoperative use of beta-blockers (OR = 2.06[1.18–3.60]) in vascular surgery and benzodiazepines RR 2.10 (1.23–3.59) prior to orthopedic surgery were significant. However, evidence is from single studies only. Where medicines were included as one possible factor among many, hypnotics had a similar risk estimate to the benzodiazepine study, with one significant and one non-significant result. Nifedipine use prior to cardiac surgery was found to be significantly associated with delirium. The non-specific grouping of psychoactive medication use preoperatively was generally higher with an associated two-to-seven-fold higher risk of postoperative delirium, while only two studies included narcotics without other agents, with one significant and one non-significant result. There was a limited number of high quality studies in the literature quantifying the direct association between preoperative medication use and postsurgical delirium. More studies are required to evaluate the association of specific preoperative medications on the risk of postoperative delirium so that comprehensive guidelines for medicine use prior to surgery can be developed to aid delirium prevention. This systematic review has been registered on PROSPERO International prospective register of systematic reviews (Registration number: CRD42016051245 ).

To identify the prevalence of potentially preventable medication-related hospitalizations amongst elderly Australian veterans by applying clinical indicators to administrative claims data. Retrospective cohort study in the Australian veteran population from 1 January 2004 to 31 December 2008. A total of 109 044 veterans with one or more hospitalizations defined by the medication-related clinical indicator set, during the 5-year study period. The prevalence of potentially preventable medication-related hospitalizations as a proportion of all hospitalizations defined by the clinical indicator set. During the 5-year study period, there were a total of 1 630 008 hospital admissions of which 216 527 (13.3%) were for conditions defined by the medication-related clinical indicator set for 109 044 veterans. The overall proportion of potentially preventable medication-related hospitalizations was 20.3% (n= 43 963). Of the 109 044 veterans included in the study, 28 044 (25.7%) had at least one potentially preventable medication-related hospitalization and 7245 (6.6%) veterans had two or more potentially preventable admissions. Conditions with both a high prevalence of hospitalization and preventability included asthma/chronic obstructive pulmonary disorder, depression and thromboembolic cerebrovascular event (23.3, 18.5 and 18.3%, respectively, were potentially preventable). Other hospitalizations that were less common but had a high level of preventability (at least 20%) included hip fracture, impaction, renal failure, acute confusion, bipolar disorder and hyperkalaemia. The results of this study highlight those conditions where hospitalizations could potentially be avoided through improved medication management. Strategies to increase the awareness, identification and resolution of these medication-related problems contributing to these hospitalizations are required in Australia.