Mortality associated with multimorbidity and polypharmacy in patients with stroke or transient ischaemic attack: A study of 8751 UK Biobank Participants.

Problem

Multimorbidity (the presence of one or more long term conditions) and polypharmacy (the prescribing of multiple medications) are common in stroke. Those with higher numbers of morbidities or medications are at higher risk of drug-drug and disease-drug interactions. Current stroke guidelines do not adequately take account of multimorbidity or polypharmacy. Our study aimed to enhance our understanding of the risk factors for multimorbidity and polypharmacy in those with stroke and importantly, any effects on mortality. We examined the following in people with stroke or TIA: the relationship between sociodemographic and lifestyle characteristics, and multimorbidity / polypharmacy; the relationship between multimorbidity / polypharmacy and all-cause mortality; which comorbid health conditions, if any, have a stronger association with all-cause mortality.

Approach

UK Biobank is an anonymized community research cohort, aged 37-73 years. Self-reported comorbidities (n=42) were identified in those with stroke / TIA. Relative risk ratios (RRR) were used to examine associations between participant characteristics and number of comorbidities and medications. Hazard Ratios (HRs) were used to examine associations between number and type of comorbidities and number of medications and all-cause mortality. Results were adjusted for age, sex, socioeconomic status, smoking and alcohol intake. All-cause mortality was studied over a median duration of 7 years (interquartile range 75 to 93 months) by linking data with national mortality records.

Findings

Included 8751 participants with stroke or TIA; mean age was 60.9 years (SD 6.7). The rate of all-cause mortality over 7 years was 8.4% (734 participants). Just over 85% of participants with stroke /TIA reported having ≥ 1 comorbidity and over 56% were on ≥5 medications. Age, socioeconomic deprivation, smoking and less frequent alcohol intake were associated with higher levels of multimorbidity and polypharmacy. Increasing multimorbidity and polypharmacy were associated with higher all-cause mortality, with mortality risk more than double for those with ≥5 morbidities compared to those with none (fully adjusted HR; 95% CI: 2.38; 1.69-3.33). The presence of cancer, coronary heart disease, diabetes or chronic obstructive pulmonary disease significantly increased risk of mortality for those with stroke / TIA.

Consequences

Better risk stratification of people with stroke who are multimorbid is important for clinicians and policy makers to inform future clinical guideline development and the planning of health service provision. Our findings support the premise that there is a need to move from disease centred to person centred care for those with stroke and TIA. Increased emphasis should be placed on understanding which combinations of polypharmacy and multimorbidity pose the greatest risk and developing evidence based approaches to manage such risks.