Lähteenvuo M, et al. - The researchers performed this study to ascertain the comparative effectiveness of pharmacologic treatments in the prevention of rehospitalization in a nationwide cohort of patients with bipolar disorder. As per findings, lithium should remain the first line of treatment in bipolar disorder, and for patients in whom lithium is not suitable, long-acting injections might offer a safe, effective option.

Methods

• In this cohort study, researchers investigated the risk of psychiatric, cardiovascular, and all-cause hospitalization from January 1, 1987, to December 31, 2012, among all patients in Finland who had been hospitalized for bipolar disorder (N = 18,018; mean follow-up time, 7.2 years) using prospectively gathered nationwide databases for hospitalization and dispensed medications.
• They performed primary analysis which was within-individual analysis; they used each individual as his or her own control to eliminate selection bias in this analysis.
• For the effect of concomitant psychotropic medications, duration of illness, and the temporal orders of exposure and nonexposure periods, this study was adjusted.
• From January 1, 1996, to December 31, 2012, they conducted statistical analysis.
• Calculation of adjusted hazard ratios (HRs) for rehospitalization was performed.

Results

• Among the cohort (9,558 women and 8,460 men; mean [SD] age, 46.6 [17.0] years), at least 1 psychiatric rehospitalization was observed for 9,721 patients (54.0%).
• In comparison between use and no use among specific agents reaching nominal statistical significance, risperidone long-acting injection (HR, 0.58 [95% CI, 0.34-1.00]), gabapentin (HR, 0.58 [95% CI, 0.44-0.77]), perphenazine long-acting injection (HR, 0.60 [95% CI, 0.41-0.88]), and lithium carbonate (HR, 0.67 [95% CI, 0.60-0.73]) were observed to be correlated with the lowest risk of psychiatric rehospitalization.
• Lithium (HR, 0.71 [95% CI, 0.66-0.76]) was associated with the lowest risk in terms of all-cause hospitalization.
• Quetiapine fumarate, the most frequently used antipsychotic treatment, demonstrated only modest effectiveness (risk of psychiatric rehospitalization: HR, 0.92 [95% CI, 0.85-0.98]; risk of all-cause hospitalization: HR, 0.93 [95% CI, 0.88-0.98]).
• Substantially better outcomes were observed with long-acting injections compared with identical oral antipsychotics (risk of psychiatric rehospitalization: HR, 0.70 [95% CI, 0.55-0.90]; risk of all-cause hospitalization: HR, 0.70 [95% CI, 0.57-0.86]).
• Sensitivity analyses revealed consistent beneficial effects only for lithium and for long-acting injections compared with their oral counterparts.