Change in diagnosis on fit notes within an episode of certified sickness absence

Little consideration has previously been given to the implications of a change in diagnosis during a sickness certification episode.

To report the extent and patterns of change in diagnosis and to identify factors associated with likelihood of change.

Sixty-eight general practices in the UK recorded details of sickness certificates (fit notes) issued to patients in a 12-month data collection period. Diagnoses on fit notes were assigned to modified READ categories.

Over 23% (3841/16400) of episodes consisting of more than one sickness certificate had a change in diagnosis during the course of the episode. Over 4% (438/10398) of initial physical health episodes had a later mental health diagnosis. Lowest rate of change was found within episodes with an initial mental health diagnosis, the highest when an unspecified physical symptom was entered on the first fit note in the episode. A change in diagnosis was more likely when the total duration of the episode was longer, the episode included more fit notes and the patient was living in a socially deprived neighbourhood. Episodes where the patient had been issued fit notes by more than one GP were more likely to have a change in diagnosis.

Change in diagnosis on fit notes is much less common when the patient has a psychological health problem.