Systematic Review of Outcome Measures in Pharmacologically Managed Chronic Pain: Informing a New Outcome Framework...

Chronic pain represents a global burden, highlighting the necessity for accurate outcome measures in treatment evaluation. This systematic review aims to identify what outcome measures and tools are applied in chronic pain primary care-based pharmacotherapy services.

The MEDLINE, Embase, and CINAHL databases, along with the reference lists of published articles, were systematically searched from 2013 to July 2023. This search included observational studies that employed pharmacological interventions recommended by the World Health Organisation pain ladder and the Scottish Intercollegiate Guidelines Network guidelines. The studies targeted chronic pain patients treated in outpatient settings and examined five predefined outcomes: health-related quality of life (HRQoL), cost-effectiveness, medication optimisation, adverse events, and patient experience. The quality of included studies was assessed using the Newcastle-Ottawa Scale (NOS).

Among the 23 studies included a total of 51 outcome measurement tools were employed to assess the five predefined outcomes, involving 44,472 patients with chronic pain. Fifteen were cohort studies, while 8 were cross-sectional surveys or questionnaire-based. Most studies focused on one to two outcomes only (n = 19; 82.6%). HRQoL emerged as the primary outcome studied across all 23 studies (100%), predominantly assessed through the Brief Pain Inventory (BPI) tool (n = 9; 39.1%). Conversely, the least studied outcomes were medication optimisation and cost-effectiveness. The timing of measurement post-intervention and follow-up durations displayed significant variability across the studies.

This review identifies gaps in enabling a more holistic assessment of pharmacotherapy services and underscores the need for enhanced consistency via standardised tools in clinical practice.