Prodromal symptoms of multiple sclerosis in primary care.

OBJECTIVE: Early diagnosis and treatment initiation significantly influence long-term disability outcome in multiple sclerosis (MS). We aimed at identifying prodromal symptoms of MS in primary care settings. METHODS: This was a nested case-control study comparing the occurrence of various symptoms in MS patients versus controls at 0 to 2, 2 to 5, and 5 to 10 years before index date (first MS record). A total of 10,204 incident MS cases were identified within the United Kingdom Clinical Practice Research Datalink between January 1, 1987 and February 28, 2016 (median age = 47 years, interquartile range [IQR] = 39-57, females = 7,308 [71.6%]). Patients were matched to 39,448 controls with no MS record by sex, year of birth, general practitioner, and year of registration (age = 47 years, IQR = 39-56, females = 28,248 [71.6%]). Odds ratios (ORs) with 95% confidence intervals (CIs) were calculated using conditional logistic regression. RESULTS: MS patients had significantly higher risk of presenting up to 10 years prior to index date with gastric, intestinal, urinary, and anorectal disturbances, anxiety, depression, insomnia, fatigue, headache, and various types of pain. MS risk progressively increased with each additional symptom presented (0-2 years: OR = 1.51, 95% CI = 1.47-1.55, p < 0.001; 2-5 years: OR = 1.29, 95% CI = 1.25-1.33, p < 0.001; 5-10 years: OR = 1.20, 95% CI = 1.15-1.26, p < 0.001). Sensitivity analyses in patients with age at index < 40 years and no neurological disturbances prior to symptoms of interest showed consistent results. INTERPRETATION: Various clinical disturbances precede MS diagnosis by several years, supporting a prodromal phase to the disease and improving our clinical knowledge of early MS. Integrating these symptoms in the diagnostic procedure may help earlier disease identification. Ann Neurol 2018.