Prevalence of potentially inappropriate prescribing in a subpopulation of older European clinical trial participants: a cross-sectional study

Older people often have multiple comorbidities and as a consequence are frequently prescribed multiple drugs. This increases their risk of adverse drug events (ADEs), extended hospital stays and mortality 1. Potentially inappropriate prescribing (PIP) describes any drug that has the potential to cause an adverse event which can outweigh its clinical benefit when compared to alternative treatment options 2. In recent years, the STOPP/START (Screening Tool of Older Persons Prescriptions, Screening Tool to Alert doctors to Right Treatment) criteria were developed and validated as an explicit measure of PIP and potential prescribing omissions (PPOs) for use in older adults (≥ 65 years) in European countries 3.  All criteria are organised according to physiological systems for ease of use 4. In 2014, the STOPP/START criteria were revised and adapted to new evidence-based guidelines, STOPP/START version 2 (STOPP/START V2), comprising 80 STOPP and 34 START criteria. The aim of this study that was recently published in the BMJ Open was to estimate and compare the prevalence and type of PIP and PPOs among a sample of community-dwelling older adults enrolled to a clinical trial across three different European countries using a subset of the STOPP/START V2 criteria.

This was a secondary analysis of the Thyroid Hormone Replacement for Subclinical Hypo-Thyroidism (TRUST) Trial dataset. The trial was conducted in four countries (Ireland, Scotland, Switzerland and the Netherlands). Community-dwelling participants aged ≥65 years with untreated subclinical hypothyroidism (SCH) were randomly assigned to levothyroxine or placebo 5. For this study, medication information was available for three of the four countries (Ireland, Switzerland [one site, Bern] and the Netherlands). A subset of the STOPP/START V2 criteria were applied, as information required for some criteria (i.e. drug strength, dose and duration of prescriptions) was not available in the TRUST dataset. Therefore, a  subset of 48/80 PIP and 22/34 PPOs indicators from the STOPP/START V2 criteria were applied to prescribed medication data for 532/737 trial participants in Ireland, Switzerland and the Netherlands.

The overall prevalence of PIP was lower in the Irish participants (8.7%), compared to the Swiss (16.7%) and Dutch (12.5%) participants (p=0.15) and was not statistically significant. The overall prevalence of PPOs was approximately one-quarter in the Swiss (25.3%) and Dutch (24%) participants and lower in the Irish (14%) participants (p=0.04) and the difference was statistically significant. The hypnotic Z-drugs were the most frequent PIP in Irish participants, (3.5%, n=4), while it was non-steroidal anti-inflammatory drug (NSAID) and oral anticoagulant combination, sulphonylureas with a long duration of action, and benzodiazepines (all 4.3%, n=7) in Swiss, and benzodiazepines (7.1%, n=18) in Dutch participants. The most frequent PPOs in Irish participants were vitamin D and calcium in osteoporosis (3.5%, n=4). In the Swiss and Dutch participants they were bone anti-resorptive/anabolic therapy in osteoporosis (9.9%, n=16, 8.6%, n=22) respectively. The odds of any PIP after adjusting for age, sex, multimorbidity and polypharmacy were ([aOR]) 3.04 (95% CI 1.33-6.95, p<0.01) for Swiss participants and aOR 1.74 (95% CI 0.79-3.85, p=0.17) for Dutch participants compared to Irish participants. The odds of any PPOs were aOR 2.48 (95% CI 1.27-4.85, p<0.01) for Swiss participants and aOR 2.10 (95% CI 1.11-3.96, p=0.02) for Dutch participants compared to Irish participants.

This was the first study to estimate and compare the prevalence and type of PIP and PPOs using a subset of the STOPP/START V2 criteria in community-dwelling older adults enrolled to a clinical trial across three different European countries. It demonstrated a significant difference in the prevalence of PPOs between the three populations. The findings from the study are an important first step to justify the need for large comparative studies using routine data. This can then help to inform policy or the development of appropriate interventions on optimising prescribing practices in older adults at a national or international level. Further research is urgently needed into the impact of system level factors as this has important implications for patient safety, healthcare provision and economic costs.

 

David O Riordan

SPHeRE programme PhD alumnus

University College Cork

Email: davidoriordan@ucc.ie

Twitter: @davidoriordan7

 

Acknowledgements

In the TRUST study, supplies of levothyroxine and matching placebo were provided free of charge by Merck KGaA, Darmstadt, Germany. Merck played no role in the design, analysis, or reporting of the trial. We would like to acknowledge the participants of the FP7 – Thyroid hormone Replacement for Untreated older adults with Subclinical hypothyroidism TRUST trial and to acknowledge financial support from this trial also (EU Project grant agreement number 278148).

 

References

  1. Fried TR, O’leary J, Towle V, et al. Health Outcomes Associated with Polypharmacy in Community‐Dwelling Older Adults: A Systematic Review. Journal of the American Geriatrics Society 2014;62(12):2261-72.
  2. Beers MH, Ouslander JG, Rollingher I, et al. Explicit criteria for determining inappropriate medication use in nursing home residents. UCLA Division of Geriatric Medicine. Arch Intern Med 1991;151(9):1825-32.
  3. Gallagher P, Ryan C, Byrne S, et al. STOPP (Screening Tool of Older Person’s Prescriptions) and START (Screening Tool to Alert doctors to Right Treatment). Consensus validation. Int J Clin Pharmacol Ther 2008;46(2):72-83.
  4. Gallagher P, Lang PO, Cherubini A, et al. Prevalence of potentially inappropriate prescribing in an acutely ill population of older patients admitted to six European hospitals. Eur J Clin Pharmacol 2011;67(11):1175-88. doi: 10.1007/s00228-011-1061-0
  5. Stott DJ, Gussekloo J, Kearney PM, et al. Study protocol; Thyroid hormone Replacement for Untreated older adults with Subclinical hypothyroidism – a randomised placebo controlled Trial (TRUST). BMC Endocr Disord 2017;17(1):6. doi: 10.1186/s12902-017-0156-8.