Changes in outpatient lithium treatment in the Netherlands during 1996-2005.

BACKGROUND

The objectives of the present study were to investigate in outpatients in the Netherlands between 1996 and 2005, changes in 1) the incidence and prevalence of lithium use and 2) lithium use patterns (discontinuation, add-on, and switch).

METHODS

Incidence and prevalence of lithium use were determined for each year between 1996 and 2005. In addition, we determined cumulative changes in lithium use (discontinuation, add-on, and switching) at three, six, 12 and 24 months for three separate time-cohorts (1998-1999, 2000-2001 and 2002-2003). Lastly, concomitant use of other drugs used in the treatment of bipolar disorders next to lithium during the 24 months after the first lithium prescription was determined for the three time-cohorts.

RESULTS

Incidence of lithium use was constant at approximately 0.2 per 1000 person-years, prevalence increased with 26% from 0.95 to 1.2 per 1000 persons. The percentage of patients receiving an add-on drug used in the treatment of bipolar disorders was constant over the three time-cohorts, with a significant decrease in use of tricyclic antidepressants. Within the patient group that stopped using lithium, more patients switched from lithium to another agent used in the treatment of bipolar disorders over calendar time, and fewer patients discontinued lithium. There was a significant increase in the use of atypical antipsychotics and valproic acid next to lithium.

LIMITATIONS

We did not know the specific diagnosis for which lithium treatment was instituted.

CONCLUSION

The changes were in line with the increase in alternatives during the last decade and in line with Dutch guidelines.