Abstract
Introduction
Olanzapine doses in adults with treatment-resistant schizophrenia or treatment-resistant schizoaffective disorder have been compared in a few open-label trials, with higher doses associated with increased symptom improvement. The most significant adverse effects observed at off-label doses above 30 mg/day have been weight gain, sedation, or drowsiness.
Methods
This single-center, retrospective cohort study aimed to evaluate patient factors and outcomes in adult patients admitted to a county psychiatric hospital that received high-dose olanzapine therapy (HD-olanzapine, ≥40 mg/day) compared with standard-dose olanzapine (SD-olanzapine, 5-30 mg/day). Patients 18 years or older were included if they received at least 5 days of scheduled olanzapine treatment for psychotic symptoms or psychosis while admitted.
Results
Subjects on HD-olanzapine (n = 139) and SD-olanzapine regimens (n = 70) were on average 35 years of age, and most were White. There was no statistical difference regarding 30-day all-cause readmissions, 30-day all-cause emergency-treatment service visits, or average duration of olanzapine therapy. The average length of stay was longer in the HD-olanzapine group (31.3 days vs 14.5, P = 0.009). Constipation was more common in the HD-olanzapine group (8.6% vs 1.4%, P = 0.0418).
Discussion
Although 30-day all-cause readmissions and emergency-treatment service visits were similar between groups, patients who received olanzapine doses of 40 mg/day or greater for at least 5 days of treatment experienced significantly longer average length of stay and more constipation during an admission.
Keywords: olanzapine, readmission, tolerability
Introduction
Guidelines recommend second-generation antipsychotics as first-line treatment for schizophrenia.1-8 Olanzapine is a second-generation antipsychotic with a manufacturer’s recommended maximum of 20 mg/day, though treatment guidelines recommend doses up to 30 mg/day.5,9 In the Clinical Antipsychotic Trials of Intervention Effectiveness study, olanzapine at doses of 7.5 to 30 mg/day (mean modal dose 20.1 mg/day) was associated with more discontinuation due to weight gain or metabolic effects among second-generation antipsychotics received by patients diagnosed with chronic schizophrenia.10 In other studies, off-label doses above 30 mg/day have been associated with a higher incidence of adverse effects.11 “High-dose olanzapine” (HD-olanzapine; generally doses >20 mg/day) has been documented in literature as an alternative therapeutic option for patients unable to tolerate clozapine. At doses of 25 to 45 mg/day, olanzapine has demonstrated comparable efficacy to 100 to 600 mg/day of clozapine, as well as few safety concerns, in at least 3 double-blinded, randomized controlled trials conducted in adult patients with treatment-resistant schizophrenia (TRS) or treatment-resistant schizoaffective disorder, ranging from 18 to 24 weeks of treatment.12-14 In 1 double-blinded, randomized controlled trial, the efficacy and safety of olanzapine, risperidone, and clozapine were compared to each other and with haloperidol in patients with TRS or treatment-resistant schizoaffective disorder. HD-olanzapine (mean dose during last 6 weeks of study of 30.4, SD = 6.6 mg/day) was associated with improvements in baseline Positive and Negative Syndrome Scale total scores, as well as positive symptoms and general psychopathology subscales, at 14 weeks of treatment, as compared with relatively lower doses of olanzapine (mean dose achieved during first period of study was 19.6, SD = 2.1 mg/day).15
Olanzapine dosages in the setting of TRS or treatment-resistant schizoaffective disorder have been compared in a few open-label trials in recent years. The relatively small sample sizes of participants who completed these studies (ranging from 4-43) included 13- to 24-week time horizons in both inpatient and outpatient settings for olanzapine doses up to 40 mg.16-19 A 20% reduction from baseline in total Positive and Negative Syndrome Scale scores was not found to be statistically significant in 2 of these studies in which subjects received olanzapine doses over 20 mg/day.17,19 Significant improvements in positive and negative symptoms were observed in 1 study, where response was defined as at least 20% reduction in Brief Psychiatric Rating Scale scores; 39.2% of olanzapine-treated patients responded to 10 to 25 mg/day, with associated EPS at these doses reported as mild.18 Available case reports show favorable benefit-risk ratios for up to 60-mg/day olanzapine administration to patients.20,21
The risk of adverse effects with HD-olanzapine has also been specifically studied in several randomized trials, often with clozapine or other antipsychotic comparator groups.12,13,15,22,23 Common adverse effects with olanzapine include postural hypotension, constipation, weight gain, dizziness, and akathisia.9 In a 2023 systematic review of studies of adult patients with TRS or related disorders treated with “high-dose” or “low-dose” olanzapine (≤20 mg/day) compared with placebo or other antipsychotics, the most significant adverse effects observed in the HD-olanzapine treatment groups in 5 of these studies were weight gain (mean weight gain 2.1-7.2 kg), sedation, or drowsiness; EPS incidence was relatively low.24 In the double-blind crossover trial where HD-olanzapine was defined as 25 mg/day, only headache was observed at a higher prevalence than in the control group.22 In the open-label studies, olanzapine doses up to 40 mg/day were not associated with any serious events.24
Available randomized controlled trials evaluating the comparative efficacy of olanzapine versus comparator agents mainly use clinical rating scales (Brief Psychiatric Rating Scale, Positive and Negative Syndrome Scale, Clinical Global Impression).12,13,15,19,22,23,25 Studies directly evaluating the associations between comparative olanzapine doses and hospitalization outcomes are lacking. A psychotropic stewardship effort led by Board-Certified Psychiatric Pharmacists proposed that this study be conducted to evaluate the real-world effectiveness of olanzapine doses via comparisons of readmission rates and lengths of stay between 2 groups (HD-olanzapine, ≥40 mg/day, as compared with SD-olanzapine, 5-30 mg/day).
Methods
This retrospective review involved data collection from an electronic medical record of adult patients admitted to a single-county, acute-care psychiatric hospital between January 1, 2019, and December 31, 2023, who received at least 5 days of scheduled olanzapine for psychosis or psychotic symptoms, as verified by medication administration record review. Patients were excluded if they had received a long-acting injectable antipsychotic within 30 days of admission, or if they received both olanzapine and clozapine during a single admission, given these agents likely impacted overall symptom control and olanzapine doses required to achieve stability while admitted. Patients were excluded if they had a documented past medical history of seizure disorders or cardiomyopathy. To increase the likelihood of capturing all readmissions and emergency room visits related to psychiatric symptom exacerbation accessible through the electronic medical record’s interoperability tool (shared patient data across different healthcare organizations), patients were excluded if they possessed a primary residence outside the state of California.
Patients with any duration of standing olanzapine orders at 40 mg/day or higher (HD-olanzapine) during the study period were identified and screened for inclusion criteria. For patients identified as having standing orders for SD-olanzapine (5-30 mg/day), patient charts were randomly selected for screening until the number reached a targeted 2:1 (HD-olanzapine:SD-olanzapine) ratio.
The primary outcome was all-cause psychiatric 30-day readmission rates after treatment with HD-olanzapine compared with SD-olanzapine during an admission. Secondary outcomes compared 30-day all-cause psychiatric emergency treatment services visit rates, hospital length of stay, continuation of antipsychotics at discharge, proportion of patients discharged on a long-acting injectable antipsychotic, discharge disposition, and reported adverse effects. Additional collected characteristics included health insurance coverage, smoking status at time of admission, history of (or comorbid) substance use disorder diagnosis at time of admission, and discharge medication regimen.
Discrete data were analyzed using Pearson’s Χ2. Continuous data were analyzed using Student’s t-test. In this study, P values < 0.05 were considered statistically significant.
This study was approved by the local institutional review board.
Results
A total of 513 patients were identified to have received scheduled doses of olanzapine of at least 40 mg/day; 374 were excluded after screening. Of patients, 139 were included in the HD-olanzapine group. Of 3386 patients identified to have received at least 5 days of scheduled olanzapine 5 to 30 mg/day, 70 random subjects that met the inclusion criteria comprised the SD-olanzapine group. Baseline characteristics (Table 1) in the HD-olanzapine group (n = 139) and SD-olanzapine group (n = 70) revealed a mean age of 35 years, with a majority of White males. There was a higher proporation of men in the HD-olanzapine group than in the SD-olanzapine group (75.5% vs 52.9%, P < 0.001). The most common primary diagnosis at discharge in both groups was schizophrenia, although there was a statistically significant difference in the distribution of diagnoses between groups, with a higher percentage of schizoaffective disorder (25.9% vs 12.8%) found in the HD-olanzapine group and a higher percentage of unspecified psychosis (25.7% vs 11.5%) and mood disorders (5.7% vs 0.7%) found in the SD-olanzapine group. There were no statistically significant differences between groups regarding health insurance coverage, smoking status, or substance use.
TABLE 1.
Baseline characteristics
| Characteristic | High-Dose Olanzapine Therapy (n = 139) | Standard-Dose Olanzapine Therapy (n = 70) | P Value |
|---|---|---|---|
| Age, yr (SD) | 35.0 (10.2) | 35.3 (12.3) | 0.852 |
| Sex, male | 105 (75.5%) | 37 (52.9%) | 0.001* |
| Race | 0.345 | ||
| White or Caucasian (Non-Hispanic/Latino; Hispanic/Latino, Mexican, Mexican American, Chicano(a)) | 101 (72.7%) | 55 (78.6%) | |
| Black or African American | 33 (23.7%) | 11 (15.7%) | |
| Asian/Pacific Islander/Other | 5 (3.6%) | 4 (5.7%) | |
| Ethnicity | 0.282 | ||
| White, Non-Hispanic/Latino | 46 (33.1%) | 30 (42.9%) | |
| Hispanic/Latino, Mexican, Mexican American, Chicano(a) | 55 (39.6%) | 25 (35.7%) | |
| Primary Discharge Diagnosis | 0.010* | ||
| Schizophrenia | 68 (48.9%) | 32 (45.7%) | |
| Schizoaffective disorder | 36 (25.9%) | 9 (12.8%) | |
| Unspecified psychosis | 16 (11.5%) | 18 (25.7%) | |
| Bipolar disorder | 17 (12.2%) | 7 (10.0%) | |
| Unspecified mood disorder | 1 (0.7%) | 4 (5.7%) | |
| MDD with psychotic features | 1 (0.7%) | – | |
| Health Insurance Coverage^ | 0.306 | ||
| Insured | 118 (84.9%) | 63 (90.0%) | |
| Uninsured | 21 (15.1%) | 7 (10.0%) | |
| Active smoker | 79 (56.8%) | 44 (62.9%) | 0.404 |
| Substance use** (Diagnosis or by history) | 38 (27.3%) | 26 (37.1%) | 0.147 |
Significance defined at P < 0.05.
Insured patients included those with active health insurance coverage from commercial plans or government insurance (including Medicare, Medicaid, and care provided by the Department of Veterans Affairs and military).
Substance use disorder (SUD) diagnosis documented in patient’s medical record discharge summary for given admission along with primary discharge diagnosis. Includes alcohol, tobacco, opiates, marijuana (cannabis, THC), stimulants (amphetamines, methamphetamines), illicit substances (cocaine), unspecified.
A summary of measured outcomes is provided in Table 2. There was no statistical difference in 30-day all-cause readmissions, 30-day all-cause emergency-treatment service visits, or average duration of olanzapine therapy between groups. The average length of stay was significantly longer in the HD-olanzapine group than the standard-dose group (31.3 vs 14.5 days, P = 0.009). Of patients who received HD-olanzapine, 68%, and 78.6% of patients who received SD-olanzapine were discharged on these regimens. The proportion of patients discharged on multiple antipsychotics was higher among the HD-olanzapine group, with 25.2% discharged on 2 or more antipsychotics compared with 11.4% of standard-dose patients (P = 0.024). Although the total number of patients with adverse effects was higher in the HD-olanzapine group (20.1% vs 11.4%), this difference did not reach statistical significance (P = 0.115). There were more reports of constipation in the HD-olanzapine group (8.6% vs 1.4%, P = 0.042).
TABLE 2.
Outcomes
| Outcome | High-Dose Olanzapine Therapy (n = 139) | Standard-Dose Olanzapine Therapy (n = 70) | P Value |
|---|---|---|---|
| 30-day all-cause readmission, n (%) | 18 (12.9) | 14 (20.0) | 0.182 |
| 30-day all-cause ETS visit, n (%) | 20 (14.4) | 8 (11.4) | 0.553 |
| Average duration of olanzapine therapy, days (SD) | 14.3 (22.0) | 11.5 (15.5) | 0.336 |
| Olanzapine discharge order, n (%)^ | 121 (87.1) | 55 (78.6) | 0.113 |
| Admission average length of stay, days (SD) | 31.3 (51.0) | 14.5 (19.9) | 0.009* |
| Number of Antipsychotics on Discharge, n (%) | 0.024* | ||
| 0 | 3 (2.2) | 2 (2.9) | |
| 1 | 93 (66.9) | 60 (85.7) | |
| 2 | 41 (29.5) | 8 (11.4) | |
| 3 | 2 (1.4) | – | |
| Discharge Disposition, n (%) | 0.066 | ||
| Self/home/independent living | 70 (50.4) | 45 (64.3) | |
| Shelter/emergency housing | 13 (9.4) | 3 (4.3) | |
| Board and care/residential care facility | 9 (6.5) | 5 (7.1) | |
| Crisis residential program | 10 (7.2) | 10 (14.3) | |
| Mental health rehabilitation center | 6 (4.3) | 1 (1.4) | |
| Institution for mental disease/psychiatric health facility | 25 (18.0%) | 5 (7.1%) | |
| Parole officer/law enforcement | 6 (4.3) | 1 (1.4) | |
| Long-acting injectable antipsychotic on discharge, n (%) | 22 (15.8) | 12 (17.1) | 0.808 |
| Time to first readmission, days (SD) | 262 (325) | 198 (256) | 0.285 |
| Adverse effect, n (%)^^ | 28 (20.1) | 8 (11.4) | 0.115 |
| Constipation | n = 12 | n = 1 | 0.042* |
| Sedation | n = 9 | n = 4 | 0.830 |
| Extrapyramidal Symptoms | n = 6 | n = 1 | 0.273 |
| Dizziness | n = 1 | n = 2 | 0.220 |
| Hypotension | n = 2 | – | 0.313 |
| Other Intolerance | – | n = 1 | 0.158 |
ETS = emergency-treatment services.
Significance defined at P < 0.05.
9 5 patients received a discharge order for olanzapine ≥40 mg upon discharge. A subsequent analysis of just these 95 patients vs 55 standard dose olanzapine resulted in P = 0.121.
Number of patients in which at least 1 adverse effect was observed. The adverse effect specific rows represent the number of observed events per adverse effect type. Patients may have reported >1 adverse effect.
Discussion
Our findings suggest that any potential clinical benefit imparted by olanzapine doses of 40 mg/day or above might not outweigh the risk of medication side effects and may be associated with a longer length of stay compared with doses of 5 to 30 mg/day. Although there were no statistically significant findings in this study (Table 2), increased reports of EPS and sedation or drowsiness at olanzapine doses over 40 mg/day have been observed in other studies evaluating safety.24,26 Weight gain has also been reported to occur at significantly higher rates at these doses, but was not a measure collected in this study.24,26 Other adverse effects, such as hyperprolactinemia and metabolic disturbances, would be informative to collect with future studies designed to detect these parameters, especially with long-term use.
This study has several limitations to note. First, the comparison between the HD- and SD-olanzapine regimens might not fully represent a true comparison between the same level of severity of illness, as it might be the case that patients with a higher burden of illness would receive a more aggressive regimen for symptom control. Given the study design, however, matching or controlling for this aspect is challenging, especially as the SD-olanzapine group was randomly selected from a large pool of subjects with variable presentations. The dosage cutoffs used to define SD- and HD-olanzapine were selected, in part, to address this; standard doses allowed for a maximum daily dose above 20 mg to include in this group, as well as patients whose clinical symptoms warranted dose titrations beyond the FDA-approved maximum.
Many patients, while admitted, received other concurrent medications including first-generation antipsychotics, mood-stabilizing medications, anxiolytics, antidepressants, antihistamines, and beta-blockers. The current study design is unable to assess concurrent medication use effects on treatment outcomes. Additionally, the effects of substance use and substance use history on presentation were not fully explored, though documented history in the study population was reported.
Several retrospective studies exploring risk factors for 7- to 30-day readmissions to psychiatric hospitals have identified length of stay as a significant risk factor, with varying findings.27-29 In 1 study, a longer index length of stay (>15 days) has been cited as a significant risk factor or to have no significant association with time to readmission.28 The average length of stay in the HD-olanzapine cohort was approximately 31 days. Other practical matters, such as delays in safe discharge planning related to placement or mental health conservatorship, likely also influenced lengths of stay. The observed lengths of stay, therefore, cannot be construed as direct reflections of medication efficacy.
Although there was no statistically significant difference between groups regarding discharge disposition, the difference approached significance (P = 0.066), and 17.3% of the HD-olanzapine patients were discharged to an institution for mental disease or psychiatric health facility, which typically have onsite psychiatrists. It should be considered that the likelihood of a patient returning to the inpatient psychiatric hospital from a facility that provides structured follow-up might be lower than that of a patient discharged to self or home.28,29 Discharge status to a private residence and level of follow-up (outpatient without psychiatrist) have been identified as significant risk factors for higher 7- and 30-day readmission rates to psychiatric hospitals, whereas discharge to a psychiatric nursing home may be a protective factor.27-29 The impact of discharge disposition on readmission rates and emergency treatment service visit rates could be highly significant.
A considerable proportion of patients who received HD-olanzapine (68.3%) were discharged on olanzapine doses of 40 mg/day or higher. Ensuring proper dose optimization and the discontinuation of inappropriate antipsychotics at discharge would also be further points to consider.
Accuracy and clarity of documentation in the patient electronic medical records limit the data collected, particularly for patient history and outcomes (ie, diagnoses at time of discharge, long-acting injectable antipsychotic use history, adverse events related to antipsychotic use).
The findings of this study serve as the basis for further investigation into the safety and efficacy of HD-olanzapine for psychosis and psychotic disorders. Future studies evaluating prior antipsychotic treatment failures and the effects of HD-olanzapine regimens in these populations could help further characterize the efficacy of olanzapine at these dosages.
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