Endocrinology Section, Internal Medicine Department, School of Medicine, Universidad de Antioquia, Medellín, Colombia.
Diabetes Education Group, Hospital Pablo Tobón Uribe, Medellín, Colombia.
J Hum Nutr Diet. 2022 Dec;35(6):1030-1042. doi: 10.1111/jhn.13017. Epub 2022 May 11.
Diabetes mellitus (DM) is one of the most prevalent chronic noncommunicable diseases globally, and the only way to reduce its complications is good glycaemic control. Insulin remains the only approved treatment for type 1 DM (T1DM) and is used by many with type 2 DM (T2DM). Carbohydrate counting is considered the ideal way to calculate meal-related insulin doses as it allows greater flexibility in diet and could, in some people, reduce the burden of the disease. The primary objective of this systematic review was to assess carbohydrate counting efficacy in reducing glycated haemoglobin (HbA ) levels and safety by not increasing hypoglycaemia risk, inducing an increase in body weight or blood lipids, or reducing the quality of life of people with T1DM.
We included randomised controlled clinical trials with a parallel-group design comparing any carbohydrate counting forms with standard care or other forms of dietary advice or insulin dose calculation in people with T1DM with a follow up period of at least 3 months and with no restrictions in language, age or settings. As a primary outcome, we consider the change of HbA levels within at least 3 months. Secondary outcomes were hypoglycaemia events, body weight changes, blood lipids levels, and the total daily insulin dose. We also evaluated health-related quality-of-life changes and questionnaires on satisfaction with treatment of diabetes.
Data from 11 studies with 899 patients were retrieved with a mean follow-up of 52 ± 35.5 weeks. Carbohydrate counting is not better in reducing HbA levels (SMD-0.24%, 95% CI -0.68 to 0.21) than all dietary advice forms. However, this finding was highly heterogeneous. We identified three studies that account for most of the heterogeneity using clustering algorithms. A second analysis excluding these studies shows a meaningful reduction in HbA levels (SMD-0.52%, 95% CI -0.82 to -0.23) with low heterogeneity. In the subgroup analysis, carbohydrate counting significantly reduces HbA levels compared with usual diabetes education. Carbohydrate counting does not relate to any substantial change in blood lipids, body weight, hypoglycaemia risk or daily insulin dose. Finally, we analysed the effect of trial duration on reduction in HbA levels and found no significant change related to time.
Carbohydrate counting is an efficacious technique to safely reduce the levels of HbA in adults and children compared with standard diabetes education, and its effect does not appear to change with prolonged time. Standardisation in reporting important outcomes such as hypoglycaemia and quality of life are vital to produce comparable evidence in carbohydrate counting clinical trials. This systematic review was registered in PROSPERO under code: CRD42020218499.
糖尿病（DM）是全球最普遍的慢性非传染性疾病之一，降低其并发症的唯一方法是良好的血糖控制。胰岛素仍然是治疗 1 型糖尿病（T1DM）的唯一批准方法，许多 2 型糖尿病（T2DM）患者也在使用。碳水化合物计数被认为是计算与膳食相关的胰岛素剂量的理想方法，因为它允许在饮食方面有更大的灵活性，并且在某些人中可以降低疾病的负担。本系统评价的主要目的是评估碳水化合物计数在降低糖化血红蛋白（HbA ）水平方面的疗效，同时不增加低血糖风险、引起体重增加或血脂升高，或降低 T1DM 患者的生活质量。
我们纳入了比较 T1DM 患者中任何形式的碳水化合物计数与标准护理或其他形式的饮食建议或胰岛素剂量计算的随机对照临床试验，这些试验具有平行组设计，随访时间至少为 3 个月，且无语言、年龄或环境限制。作为主要结局，我们考虑至少 3 个月内 HbA 水平的变化。次要结局是低血糖事件、体重变化、血脂水平和每日胰岛素总剂量。我们还评估了与健康相关的生活质量变化以及糖尿病治疗满意度的问卷。
共检索到 11 项研究，共 899 例患者的数据，平均随访 52±35.5 周。碳水化合物计数在降低 HbA 水平方面并不优于所有饮食建议形式（SMD-0.24%，95%CI-0.68 至 0.21）。然而，这一发现存在高度异质性。我们使用聚类算法确定了三项占大多数异质性的研究。排除这些研究后进行的第二次分析显示，HbA 水平有明显降低（SMD-0.52%，95%CI-0.82 至-0.23），且异质性较低。在亚组分析中，碳水化合物计数与常规糖尿病教育相比，可显著降低 HbA 水平。碳水化合物计数与血脂、体重、低血糖风险或每日胰岛素剂量无明显变化。最后，我们分析了试验持续时间对 HbA 水平降低的影响，未发现与时间相关的显著变化。
与标准糖尿病教育相比，碳水化合物计数是一种安全有效的降低成人和儿童 HbA 水平的技术，其效果似乎不会随时间延长而改变。在碳水化合物计数临床试验中，报告重要结局（如低血糖和生活质量）的标准化至关重要，以产生可比较的证据。本系统评价已在 PROSPERO 中注册，注册号为 CRD42020218499。
