Department of Clinical Biochemistry, University Hospitals of North Midlands NHS Trust, Stoke-on-Trent, Staffordshire, UK.
School of Medicine, Keele University, Keele, Stoke-on-Trent, Staffordshire, UK.
BMC Psychiatry. 2021 Jan 12;21(1):32. doi: 10.1186/s12888-020-03023-y.
Bipolar disorder is the fourth most common mental health condition, affecting ~ 1% of UK adults. Lithium is an effective treatment for prevention of relapse and hospital admission, and is widely recommended as a first-line treatment. We previously showed in other areas that laboratory testing patterns are variable with sub-optimal conformity to guidance. We therefore examined lithium results and requesting patterns relative to monitoring recommendations.
Data on serum lithium levels and intervals between requests were extracted from Clinical Biochemistry laboratory information systems at the University Hospitals of North Midlands, Salford Royal Foundation Trust and Pennine Acute Hospitals from 2012 to 2018 (46,555 requests; 3371 individuals). Data were examined with respect to region/source of request, age and sex.
Across all sites, lithium levels on many requests were outside the recommended UK therapeutic range (0.4-0.99 mmol/L); 19.2% below the range and 6.1% above the range (median [Li]: 0.60 mmol/L). A small percentage were found at the extremes (3.2% at < 0.1 mmol/L, 1.0% at ≥1.4 mmol/L). Most requests were from general practice (56.3%) or mental health units (34.4%), though those in the toxic range (≥1.4 mmol/L) were more likely to be from secondary care (63.9%). For requesting intervals, there was a distinct peak at 12 weeks, consistent with guidance for those stabilised on lithium therapy. There was no peak at 6 months, as recommended for those aged < 65 years on unchanging therapy, though re-test intervals in this age group were more likely to be longer. There was a peak at 0-7 days, reflecting those requiring closer monitoring (e.g. treatment initiation, toxicity). However, for those with initial lithium concentrations within the BNF range (0.4-0.99 mmol/L), 69.4% of tests were requested outside expected testing frequencies.
Our data showed: (a) lithium levels are often maintained at the lower end of the recommended therapeutic range, (b) patterns of lithium results and testing frequency were comparable across three UK sites with differing models of care and, (c) re-test intervals demonstrate a noticeable peak at the recommended 3-monthly, but not at 6-monthly intervals. Many tests were repeated outside expected frequencies, indicating the need for measures to minimise inappropriate testing.
双相情感障碍是第四大常见精神健康状况，影响英国成年人的比例约为 1%。锂是预防复发和住院的有效治疗方法，被广泛推荐为一线治疗药物。我们之前在其他领域表明，实验室检测模式存在差异，不符合指导原则的情况并不少见。因此，我们检查了锂检测结果和请求模式与监测建议的相关性。
从 2012 年至 2018 年，我们从英国诺丁汉中部大学医院、索尔福德皇家基金会信托和奔宁急性医院的临床生化实验室信息系统中提取血清锂水平和请求间隔的数据；共涉及 46555 次请求和 3371 人。根据请求的来源/区域、年龄和性别对数据进行了检查。
在所有地点，许多请求的锂水平都超出了英国治疗范围（0.4-0.99mmol/L）；低于范围的占 19.2%，高于范围的占 6.1%（中位数[Li]：0.60mmol/L）。有一小部分处于极端水平（<0.1mmol/L 占 3.2%，≥1.4mmol/L 占 1.0%）。大多数请求来自普通诊所（56.3%）或心理健康科（34.4%），但在毒性范围内（≥1.4mmol/L）的请求更可能来自二级保健（63.9%）。对于请求间隔，12 周时出现了一个明显的高峰，这与锂治疗稳定患者的指导原则一致。在推荐的 6 个月时没有高峰，这是因为建议<65 岁且没有改变治疗方案的患者应该每 6 个月进行一次重新检测，不过这个年龄段的重新检测间隔可能会更长。在 0-7 天之间出现了一个高峰，这反映了需要更密切监测的情况（例如治疗开始时、出现毒性）。然而，对于那些初始锂浓度在 BNF 范围内（0.4-0.99mmol/L）的患者，69.4%的检测请求是在预期检测频率之外进行的。
我们的数据显示：（a）锂水平通常维持在推荐治疗范围的较低端，（b）来自三个具有不同护理模式的英国地点的锂检测结果和检测频率模式相似，（c）重新检测间隔在推荐的 3 个月时出现明显高峰，但在 6 个月时没有高峰。许多检测请求是在预期频率之外进行的，这表明需要采取措施减少不必要的检测。
