Follow up of patients presenting with fatigue to an infectious diseases clinic.

OBJECTIVES: To determine the symptomatic and functional status during follow up of patients referred to hospital with unexplained fatigue and to identify patient variables associated with persistent functional impairment. DESIGN: Follow up by postal questionnaire six weeks to four years (median 1 year) after initial clinical assessment of patients referred to hospital during 1984-8. SETTING: Infectious diseases outpatient clinic in a teaching hospital. PATIENTS: 200 consecutive patients with fatigue of uncertain cause for at least six weeks; 177 fulfilled the inclusion criteria. MAIN OUTCOME MEASURES: Findings at initial assessment; current symptoms, beliefs about the cause of illness, coping behaviours emotional disorder, social variables including membership of self help organizations, and degrees of recovery and functional impairment from questionnaire responses. RESULTS: 144 (81%) patients returned completed questionnaires. Initial assessment did not indicate the cause of fatigue, other than preceding infection. The proportion of patients with functional impairment was significantly smaller with longer follow up (33% (11/33) at two to four years, 73% (29/40) at six weeks to six months; chi 2 for trend = 12.5, df = 1; p less than 0.05). Functional impairment was significantly associated with belief in a viral cause of the illness (odds ratio = 3.9; 95% confidence interval 1.5 to 9.9), limiting exercise (3.2; 1.5 to 6.6), avoiding alcohol (4.5; 1.8 to 11.3), changing or leaving employment (3.1; 1.4 to 6.9), belonging to a self help organization (7.8; 2.5 to 23.9), and current emotional disorder (4.4; 2.0 to 9.3). CONCLUSIONS: Short term prognosis for recovery of function was poor but improved with time. Most patients had made a functional recovery by two years after initial clinic attendance. Impaired functioning was more likely with certain patient characteristics. Prospective studies are required to clarify whether these associations are the consequences of a more disabling illness or indicate factors contributing to impaired function.