Abstract：
OBJECTIVE: In response to Health Canada\'s March 2020 directive, patients on clozapine for over 12 months were allowed to extend hematological testing intervals from 4 to 8 weeks during the COVID-19 pandemic. We hypothesized that this change would not affect the timely detection of hematological abnormalities in patients with severe mental illness.
METHODS: A chart review was conducted of patients at the Royal Ottawa who were prescribed clozapine from March 2019 to March 2021. We analyzed clinical and hematological data from electronic health records and Clozaril Support and Assistance Network database to compare occurrences of hematological abnormalities [leukopenia (white blood cell count <3.5 × 109/L) and agranulocytosis (absolute neutrophil count <0.5 × 109/L)] from March 17, 2020 to March 16, 2021, between standard and extended monitoring protocols using binomial logistic and zero-inflated negative binomial regressions.
RESULTS: Of 621 patients, 196 were on extended blood monitoring, and 425 followed standard blood monitoring. Clozapine dose did not differ between groups (standard: 370 ± 201 mg; extended: 352 ± 172 mg; P = .14, ds = 0.10). Clozapine treatment duration up to March 2021 was 12.6 ± 8.3 years, with the extended group (10 ± 7.9 years) having a significantly (P < .01, ds = 0.50) shorter duration than the standard (14 ± 8.2 years). Extended monitoring did not significantly impact likelihood of detecting hematological abnormalities (OR = 0.83, 95% CI [0.58,1.41], P = .55) after controlling for age, sex, total bloodwork, and other psychotropics associated with neutrophil counts (ie, valproate, olanzapine). No patient on the extended regimen developed agranulocytosis.
CONCLUSIONS: Reducing blood monitoring frequency in patients on clozapine for more than 12 months did not compromise detection of hematological abnormalities.
METHODS: A chart review was conducted of patients at the Royal Ottawa who were prescribed clozapine from March 2019 to March 2021. We analyzed clinical and hematological data from electronic health records and Clozaril Support and Assistance Network database to compare occurrences of hematological abnormalities [leukopenia (white blood cell count <3.5 × 109/L) and agranulocytosis (absolute neutrophil count <0.5 × 109/L)] from March 17, 2020 to March 16, 2021, between standard and extended monitoring protocols using binomial logistic and zero-inflated negative binomial regressions.
RESULTS: Of 621 patients, 196 were on extended blood monitoring, and 425 followed standard blood monitoring. Clozapine dose did not differ between groups (standard: 370 ± 201 mg; extended: 352 ± 172 mg; P = .14, ds = 0.10). Clozapine treatment duration up to March 2021 was 12.6 ± 8.3 years, with the extended group (10 ± 7.9 years) having a significantly (P < .01, ds = 0.50) shorter duration than the standard (14 ± 8.2 years). Extended monitoring did not significantly impact likelihood of detecting hematological abnormalities (OR = 0.83, 95% CI [0.58,1.41], P = .55) after controlling for age, sex, total bloodwork, and other psychotropics associated with neutrophil counts (ie, valproate, olanzapine). No patient on the extended regimen developed agranulocytosis.
CONCLUSIONS: Reducing blood monitoring frequency in patients on clozapine for more than 12 months did not compromise detection of hematological abnormalities.
摘要：
目标：为了响应加拿大卫生部2020年3月的指令，在COVID-19大流行期间,接受氯氮平治疗超过12个月的患者可将血液学检测间隔延长4~8周.我们假设这种变化不会影响严重精神疾病患者血液学异常的及时发现。
方法：对2019年3月至2021年3月在皇家渥太华接受氯氮平处方的患者进行了图表审查。我们分析了来自电子健康记录和Clozaril支持和援助网络数据库的临床和血液学数据，以比较血液异常的发生[白细胞减少症（白细胞计数<3.5×109/L）和粒细胞缺乏症（绝对中性粒细胞计数<0.5×109/L）]从2020年3月17日至2021年3月16日，在标准和扩展监测协议之间使用二项逻辑逻辑和零膨胀负二项回归。
结果：在621例患者中，196人接受了长期血液监测，425人遵循标准血液监测。两组间的氯氮平剂量没有差异（标准：370±201mg；延长：352±172mg；P=.14，ds=0.10）。截至2021年3月，氯氮平治疗时间为12.6±8.3年，扩展组（10±7.9年）的持续时间显着（P<0.01，ds=0.50）比标准（14±8.2年）短。延长监测并不显著影响检测血液学异常的可能性(OR=0.83,95%CI[0.58,1.41],P=.55）控制年龄后，性别,总血液，和其他与中性粒细胞计数相关的精神药物(即，丙戊酸盐,奥氮平）。延长方案的患者没有出现粒细胞缺乏症。
结论：减少使用氯氮平超过12个月的患者的血液监测频率并不影响血液学异常的检测。
方法：对2019年3月至2021年3月在皇家渥太华接受氯氮平处方的患者进行了图表审查。我们分析了来自电子健康记录和Clozaril支持和援助网络数据库的临床和血液学数据，以比较血液异常的发生[白细胞减少症（白细胞计数<3.5×109/L）和粒细胞缺乏症（绝对中性粒细胞计数<0.5×109/L）]从2020年3月17日至2021年3月16日，在标准和扩展监测协议之间使用二项逻辑逻辑和零膨胀负二项回归。
结果：在621例患者中，196人接受了长期血液监测，425人遵循标准血液监测。两组间的氯氮平剂量没有差异（标准：370±201mg；延长：352±172mg；P=.14，ds=0.10）。截至2021年3月，氯氮平治疗时间为12.6±8.3年，扩展组（10±7.9年）的持续时间显着（P<0.01，ds=0.50）比标准（14±8.2年）短。延长监测并不显著影响检测血液学异常的可能性(OR=0.83,95%CI[0.58,1.41],P=.55）控制年龄后，性别,总血液，和其他与中性粒细胞计数相关的精神药物(即，丙戊酸盐,奥氮平）。延长方案的患者没有出现粒细胞缺乏症。
结论：减少使用氯氮平超过12个月的患者的血液监测频率并不影响血液学异常的检测。
