Can antipsychotic monotherapy prevent hospitalizations in patients with schizophrenia?

A recent study has shown that antipsychotic monotherapy does not reduce the risk of hospitalization for severe physical health problems when compared with polypharmacy in patients with schizophrenia.

Using the Finnish nationwide inpatient care register, a total of 61,889 patients with schizophrenia (mean age 46.7 years, 50.3 percent men) were identified and followed from 1996 to 2017 (median follow-up, 14.8 years).

The investigators then compared antipsychotic polypharmacy with monotherapy in seven dosage categories (ie, <0.4, 0.4 to <0.6, 0.6 to <0.9, 0.9 to <1.1, 1.1 to <1.4, 1.4 to <1.6, and ≥1.6 defined daily doses [DDD] per day) in terms of risk of severe physical morbidity, as indicated by nonpsychiatric and cardiovascular hospitalizations. Selection bias was eliminated using within-individual analysis.

The risk of nonpsychiatric hospitalization was significantly lower in the polypharmacy group at all total dosage categories above 1.1 DDDs/day, with differences up to ‒13 percent when compared with the monotherapy group of the same dosage category (1.1 to <1.4 DDDs/day: adjusted hazard ratio [aHR], 0.91, 95 percent confidence interval [CI], 0.87‒0.95; 1.4 to <1.6 DDDs/day: aHR, 0.91, 95 percent CI, 0.86‒0.96; ≥1.6 DDDs/day: aHR, 0.87, 95 percent CI, 0.84‒0.89).

Likewise, the risk of cardiovascular hospitalization was markedly lower for polypharmacy at the highest total dosage category (‒18 percent; aHR, 0.82, 95 percent CI, 0.72‒0.94).

“The results from the comparisons between monotherapy and no use and between polypharmacy and no use were in line with the primary comparison of polypharmacy and monotherapy within the same individual,” the investigators said.

Notably, comparison of any polypharmacy use and any monotherapy use revealed no significant difference in nonpsychiatric or cardiovascular hospitalization.

“Treatment guidelines should not encourage use of monotherapy instead of antipsychotic polypharmacy without any existing evidence on the safety issues,” the investigators said.