Polypharmacy and multiple sclerosis: A population-based study

Anibal Chertcoff, Huah Shin Ng, Feng Zhu, Yinshan Zhao, Helen Tremlett

Research output: Contribution to journalArticlepeer-review

7 Citations (Scopus)
36 Downloads (Pure)


Background: Little is known about polypharmacy and multiple sclerosis (MS). Objectives: To estimate polypharmacy prevalence in a population-based MS cohort and compare persons with/without polypharmacy. Methods: Using administrative and pharmacy data from Canada, we estimated polypharmacy prevalence (⩾5 concurrent medications for >30 consecutive days) in MS individuals in 2017. We compared the characteristics of persons with/without polypharmacy and described the number of polypharmacy days, the most common medication classes contributing to polypharmacy and hyper-polypharmacy prevalence (⩾10 medications). Results: Of 14,227 included individuals (75% women), mean age = 55.4 (standard deviation (SD): 13.2) years; 28% (n = 3995) met criteria for polypharmacy (median polypharmacy days = 273 (interquartile range (IQR): 120–345)). Odds of polypharmacy were higher for women (adjusted odds ratio (aOR) = 1.14; 95% confidence intervals (CI):1.04–1.25), older individuals (aORs 50–64 years = 2.04; 95% CI:1.84–2.26; ⩾65 years = 3.26; 95% CI: 2.92–3.63 vs. <50 years), those with more comorbidities (e.g. ⩾3 vs. none, aOR = 6.03; 95% CI: 5.05–7.22) and lower socioeconomic status (SES) (e.g. most (SES-Q1) vs. least deprived (SES-Q5) aOR = 1.64; 95% CI: 1.44–1.86). Medication classes most commonly contributing to polypharmacy were as follows: antidepressants (66% of polypharmacy days), antiepileptics (47%), and peptic ulcer drugs (41%). Antidepressants were most frequently co-prescribed with antiepileptics (34% of polypharmacy days) and peptic ulcer drugs (27%). Five percent of persons (716/14,227) experienced hyper-polypharmacy. Conclusion: More than one in four MS persons met criteria for polypharmacy. The odds of polypharmacy were higher for women, older persons, and those with more comorbidities, but lower SES.

Original languageEnglish
Pages (from-to)107-118
Number of pages12
JournalMultiple Sclerosis Journal
Issue number1
Publication statusPublished - Jan 2023


  • MS
  • pharmacoepidemiology
  • polypharmacy
  • population-based data
  • prescription medication use


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