Incidence of Lyme disease in the United Kingdom and association with fatigue: a population-based, historical cohort study

Objectives To evaluate incidence rates of Lyme disease in the UK and to investigate a possible association with subsequent fatigue Design Population-based historical cohort study with a comparator cohort matched by age, sex, and general practice Setting Patients treated in UK general practices contributing to IQVIA Medical Research Data Participants 2,130 patients with a first diagnosis of Lyme disease between 2000 and 2018, and 8,510 randomly-sampled matched comparators, followed-up for a median time of 3 years and 8 months. Main outcome measures Time from Lyme disease diagnosis to consultation for any fatigue-related symptoms or diagnosis and for myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS). Adjusted hazard ratios (HRs) were estimated from Cox models. Results Average incidence rate for Lyme disease across the UK was 5.18 per 100,000 py between 2000 and 2018, increasing from 2.55 in 2000 to 9.33 in 2018. In total 929 events of any types of fatigue were observed, i.e. an incidence rate of 307.90 per 10,000 py in the Lyme cohort (282 events) and 165.60 in the comparator cohort (647 events). Effect of Lyme disease on any subsequent fatigue varied by index season with highest adjusted HRs in autumn [3.14 (95%CI: 1.92 to 5.13)] and winter [2.23 (1.21 to 4.11)]. Incidence rates of ME/CFS were 11.16 per 10,000 py in Lyme patients (12 events) and 1.20 in comparators (5 events), corresponding to an adjusted HR of 16.95 (5.17 to 55.60). Effect on any types of fatigue and ME/CFS was attenuated 6 months after diagnosis but still clearly visible. Conclusions UK primary care records provided strong evidence that Lyme disease was associated with acute and chronic fatigue. Albeit weaker, these effects persisted beyond 6 months, suggesting that patients and healthcare providers should remain alert to fatigue symptoms months to years following Lyme disease diagnosis.