A prospective cohort study to determine prognostic factors associated with outcomes in primary care attenders with unexplained physical symptoms

Background: Unexplained physical symptoms (UPS) that lack an organic explanation, even after appropriate investigation, are extremely common amongst UK primary care attenders but knowledge about their outcome is limited. / Aim: In a cohort of adult primary care attenders with UPS, this study aims to: 1) Investigate the outcome, in terms of the presence of UPS at six months follow-up and 2) Identify prognostic factors associated with somatic symptom severity, quality of life, anxiety, depression and health care use at six months follow-up. / Methods / Screening: Consecutive adults attending nine general practices completed a screening questionnaire to identify those with UPS. / Cohort study: Eligible participants completed the baseline questionnaire that enquired about somatic symptoms, quality of life, psychological well-being and past health and social history, and were followed-up after six months. / Results / Screening: Questionnaires were completed by 73% (2,826/3,896) of eligible attenders. Over two-thirds were female, median age was 42 years (IQR 30, 55) and median symptom severity score, based on the PHQ-15 was 7 (IQR 4, 11). Most (2,425/2,826 (86%)) had at least one UPS and around half (1,393/2,826 (49%)) had symptoms that were all unexplained (no explanation or diagnosis for any of their symptoms). Just under half (1,248/2,826, (44%)), had an explanation for their symptoms that included functional diagnoses (100/2,826 (4%)), psychological explanations (187/2,826 (7%)), or physical explanations or diagnoses (921/2,826 (33%)). / Cohort study: The cohort included 294 participants, were largely female (231/294 (79%)), with a median age of 44 years (IQR 32, 57)) and diverse ethnicity (43% white British). At baseline, the cohort had a high level of morbidity, with moderately severe somatic symptoms (11.5 SD 4.9). Most reported experiencing their symptoms for longer than a year. A third had clinically significant comorbid depression and anxiety. / Outcome: There was 245/294 (83%) followed-up at six months; mean PHQ-15 score was 10.5 (SD 5.3). Over a half reported unexplained symptoms (135/245 (55%)), just under half (103/245 (42%)) reported symptoms were still under investigation and only 26/245 (11%) reported that their symptoms had resolved. Options were not mutually exclusive and participants could choose more than one. The predictors of more severe somatic symptoms at follow-up were being female (B=1.31, 95% CI 0.12 to 2.50), higher somatic symptom severity (B=0.53, 95% CI 0.42 to 0.64), experience of childhood physical abuse (B=1.86 95% CI 0.27 to 3.45), perception of poor financial well-being (B=1.90, 95% CI 0.89 to 2.91) and lower physical functioning at baseline (B=-0.10, 95% CI -0.15 to -0.04). / Conclusion: Most people with UPS and high symptom severity are unlikely to improve over six months. Historical and current difficulties are associated with higher somatic symptom severity at follow-up. Future work should determine whether these findings are maintained over longer periods. The value of developing prognostic prediction models based on factors identified in this study should be explored.