Changes in bodily complaints (PHQ-15) over six years in a large general population sample

OBJECTIVE: The Patient Health Questionnaire-15 (PHQ-15) is a widely used instrument for measuring bodily complaints. The aims of this study were to analyze changes of bodily complaints over a six-year period in a large general population community sample, to test age and sex differences in these changes, and to examine associations between these changes and changes in other health-related variables.

METHODS: A total of 4821 adult subjects took part this longitudinal study at baseline (t1) and six years later (t2). The participants completed the PHQ-15 and several other questionnaires.

RESULTS: Over the six-year period, the mean score of the complaints increased from 5.18 ± 3.67 to 5.75 ± 3.97. The highest increase in terms of effect sizes was found for sexual pain/problems. While the increase in the PHQ-15 mean score was nearly identical for males and females, there were age differences in these increase rates: Participants of the oldest age group (70 years and above) experienced the greatest increase in complaints. Participants from lower socioeconomic levels also reported high increases in complaints. The correlation between the t1 and the t2 PHQ-15 score was r = 0.66. Changes in complaints from t1 to t2 were associated with changes in multiple other variables such as anxiety, social support, optimism, life satisfaction, and quality of life.

CONCLUSION: The data reported here can be used to better interpret changes in patients' health state over several years.