Use of prescribed analgesics before and after a standardised chiropractic care programme among patients with lumbar spinal stenosis: a nationwide cohort study

BACKGROUND: Patients with degenerative lumbar spinal stenosis (LSS) commonly use analgesics despite not being recommended by clinical guidelines. However, detailed knowledge of utilisation patterns is limited. This study aimed to describe prescribed analgesic use before, during, and after enrolment in a standardised chiropractic care programme, and to examine associations between patient characteristics and continued analgesic use after the programme. METHODS: This cohort study included patients with LSS enrolled in the chiropractic care programme between 1 April 2017 and 31 December 2022, identified via the Danish National Health Service Register. The programme provides guideline-based non-pharmacological care, structured follow-up, and coordination with the patient's general practitioner. Data on dispensed analgesics were retrieved from the Danish National Prescription Registry. Quarterly prevalence of analgesic use (≥ 1 dispensed prescriptions) and defined daily doses per 1000 individuals were calculated for the year before enrolment, 3 months during, and the year after the programme. The distribution of use was assessed using Lorenz curves and Gini coefficients. Associations between patient characteristics and continued analgesic use (≥ 1 dispensed prescriptions in ≥ 2 of 4 consecutive quarters) after the programme among existing users were examined using robust Poisson regression. RESULTS: Of the 7294 included patients, 45% used analgesics in the year before enrolment. Use of paracetamol, non-steroidal anti-inflammatory drugs (NSAID), opioids, and gabapentinoids increased in the year before enrolment, peaked during the programme, and generally declined after. Ten percent of analgesic users accounted for approximately 43%, 49%, 68%, and 57% of the total use of paracetamol, NSAIDs, opioids, and gabapentinoids, respectively. Female sex, having one comorbidity, and pre-existing use of paracetamol, opioid, or gabapentinoid were associated with a 5-16% higher risk of continued use, whereas long-cycle higher education was associated with a 13% lower risk. CONCLUSIONS: Analgesic use increased before enrolment, peaked during the programme, and then declined after. A small proportion of analgesic users accounted for a large share of the total use. Sociodemographic and health-related factors, and pre-existing analgesic use were associated with continued use. These findings highlight the complexity of analgesic use in this population and emphasise the need for deprescribing strategies that take this complexity into account.