Q-fever patients suffer from impaired health status long after the acute phase of the illness: results from a 24-month cohort study.

Objectives: During the largest Q-fever outbreak ever reported, a cohort study was established to assess the health status of Q-fever patients over a 24-month period and to identify factors associated with health status.

Methods: Laboratory-confirmed Q-fever patients participated at six time points after onset of illness. Scores on twelve subdomains from two health status instruments were calculated for each time point to determine progression and compare to reference groups.

Results: The study included 336 Q-fever patients. There is a significant linear improvement over time in nine of the twelve health status subdomains. For example, the proportion of patients with severe fatigue improved from 73.0% at three months to 60.0% at twelve months and 37.0% at twenty-four months, but this was still high compared to a healthy reference group (2.5%). For the three most severely affected subdomains -'Fatigue', 'General Quality of Life' and 'Role Physical'- the baseline characteristics significantly associated with a long-term reduced health status were being female, being a young adult and having pre-existing health problems.

Conclusions: Despite a significant linear improvement over time in nine of the twelve health status subdomains, more than one out of three patients still suffered from a reduced health status at 24 months.