Prediagnostic prescription patterns in multiple sclerosis: a UK-based longitudinal linked data study

BACKGROUND: Early detection of multiple sclerosis (MS) could improve patient outcomes. Changes in clinical activity before MS diagnosis may represent 'diagnostic windows' for earlier detection. AIM: To determine whether certain prescriptions are more common in patients with MS and examine prescription patterns prediagnosis in the UK. DESIGN AND SETTING: Case-control study using routinely collected primary care data. Patients in the case group had an MS diagnosis (2001-2022) and patients in the control group were matched by birth year. METHOD: Multivariable conditional logistic regression adjusting for sex and socioeconomic status (SES) examined associations between MS diagnosis and prescriptions for anxiety/depression, migraine, lower urinary tract symptoms (LUTS), urinary tract infection (UTI) treatments, sleep disorder, gastrointestinal (GI) symptoms, and erectile dysfunction (ED) in the 0-2, 2-5, 5-10 years prediagnosis/match date. Poisson regression adjusting for age, sex, and SES estimated the inflection points in the case group at which the rate of prescriptions changed from baseline, identifying the start of diagnostic windows. RESULTS: In total, there were 9662 patients in the case group and 56 455 in the control group. Positive associations were found between seven prescriptions and MS diagnosis, with highest odds ratios (3-7 times) in the 2 years prediagnosis. In the all-prescription analysis, inflection points were identified for: GI (69-72 months, 95% confidence interval [CI] = 51 to 90), LUTS (69-72 months, 95% CI = 30 to 111), UTI (66-69 months, 95% CI = 45 to 90), migraine (63-66 months, 95% CI = 27 to 102), ED (60-63 months, 95% CI = 30 to 93), and anxiety/depression (9-12 months, 95% CI = 3 to 18). CONCLUSION: Prescriptions for symptoms of possible MS were more common in the case group than the control group up to 10 years prediagnosis. Prescription rates changed years prediagnosis, indicating potential opportunities for earlier detection, but broad CIs demonstrated uncertainty regarding diagnostic window duration.