The four week time frame for somatic symptom questionnaires reflects subjective symptom burden best

Various questionnaires are available to assess somatic symptom burden, however their assessment time frames vary largely. The aim of this study was to investigate the most relevant assessment time frame for somatic symptoms by relating somatic symptom burden, with varying time frames, to quality of life (QoL) and health anxiety as indicators for clinical relevance of symptoms.

This study was performed in data derived from a convenience sample of 3477 participants (age: 48.0 (SD 14.1), 66.4% female) of the Dutch research platform HowNutsAreTheDutch. Symptom burden was assessed using all items from the Patient Health Questionnaire-15 (PHQ-15) and 6 items of the Symptom Checklist-90 SOM (SCL-90 SOM). Five versions of the questionnaire were constructed, which evaluated symptom burden during the past 24h, 1week, 2weeks, 4weeks, and 3months.

Symptom burden significantly increased with each step increase in time frame until 4weeks, with no further increase when comparing 4weeks and 3months. The time frame of 4weeks provided the strongest associations between somatic symptom burden and health anxiety (B=1.635; 95%CI: 1.368 to 1.938; p≤0.001). This was also true when analysing the association between QoL and the symptom groups of musculoskeletal (B=-1.54; 95%CI: -1.93 to -1.16;p≤0.001) and gastrointestinal symptoms (B=-0.71; 95%CI: -0.96 to -0.47;p≤0.001).

An assessment time frame of 4weeks for somatic symptom questionnaires reflects clinically relevant somatic symptom burden in terms of QoL and health anxiety best, followed by the 3months' time frame.