To assess the presence of a seasonal effect on fatigue, pain and dryness in primary Sjögren's syndrome (pSS).
Data (date; visual analogue scales (VAS) for pain, fatigue and dryness) were extracted from three randomised placebo-controlled trials (RCTs) evaluating infliximab (TRIPSS; n = 103 patients), hydroxychloroquine (JOQUER; n = 120 patients) and rituximab (TEARS; n = 120 patients) and from the 5-year follow-up of the ASSESS prospective cohort (n = 395 patients). Data were analysed at each visit for each patient, according to the day, the month of the year and the season. Linear mixed models were used to take into account the repeated structure of the data and to analyse a potential cyclic effect.
A total of 744, 584, 848 and 682 pain, fatigue and dryness VASs were collected on 632 subjects in spring, summer, fall and winter, respectively. No significant difference was observed in pain, fatigue and dryness, according to the month of the year or the season (all p values > 0.05).
In pSS, seasonality does not affect patient-reported outcomes (PROs) on fatigue, pain and dryness.