Peninsula NIHR Clinical Research Facility, Peninsula Medical School, University of Exeter, Exeter, UK.
Diabet Med. 2012 Jan;29(1):90-3. doi: 10.1111/j.1464-5491.2011.03428.x.
Serum C-peptide can be used in Type 2 diabetes as a measure of endogenous insulin secretion, but practicalities of collection limit its routine clinical use. Urine C-peptide creatinine ratio is a non-invasive alternative that is stable for at least 3 days at room temperature in boric acid preservative. We aimed to assess the utility of urine C-peptide creatinine ratio in individuals with Type 2 diabetes as an alternative to serum C-peptide.
We assessed, in 77 individuals with Type 2 diabetes, the reproducibility of, and correlations between, fasting and postprandial urine C-peptide creatinine ratio and serum C-peptide, and the impact of renal impairment (estimated glomerular filtration rate < 60 ml min(-1) 1.73 m(-2)) on these correlations.
Urine C-peptide creatinine ratio was at least as reproducible as serum C-peptide [fasting coefficient of variation mean (95% CI): 28 (21-35)% vs. 38 (26-59)% and 2-h post-meal 26 (18-33)% vs. 27 (20-34)%. Urine C-peptide creatinine ratio 2 h post-meal was correlated with stimulated serum C-peptide, both the 2-h value (r = 0.64, P < 0.001) and the 2-h area under the C-peptide curve (r = 0.63, P < 0.001). The association seen was similar in patients with and without moderate renal impairment (P = 0.6).
In patients with Type 2 diabetes, a single urine C-peptide creatinine ratio is a stable, reproducible measure that is well correlated with serum C-peptide following meal stimulation, even if there is moderate renal impairment. Urine C-peptide creatinine ratio therefore has potential for use in clinical practice in the assessment of Type 2 diabetes.
血清 C 肽可用于 2 型糖尿病，作为内源性胰岛素分泌的衡量标准，但由于采集的实际情况限制了其常规临床应用。尿 C 肽/肌酐比值是一种非侵入性替代方法，在室温下用硼酸防腐剂保存至少 3 天是稳定的。我们旨在评估 2 型糖尿病患者的尿 C 肽/肌酐比值作为血清 C 肽替代物的实用性。
我们评估了 77 例 2 型糖尿病患者空腹和餐后尿 C 肽/肌酐比值与血清 C 肽的重复性和相关性，以及肾功能损害（估计肾小球滤过率 < 60 ml min(-1) 1.73 m(-2)）对这些相关性的影响。
尿 C 肽/肌酐比值与血清 C 肽一样具有良好的重复性[空腹变异系数平均值（95%置信区间）：28（21-35）%比 38（26-59）%和 2 小时餐后 26（18-33）%比 27（20-34）%]。餐后 2 小时尿 C 肽/肌酐比值与刺激后血清 C 肽相关，两者的 2 小时值（r = 0.64，P < 0.001）和 C 肽曲线下 2 小时面积（r = 0.63，P < 0.001）相关。在肾功能中度损害的患者和无中度肾功能损害的患者中，这种相关性相似（P = 0.6）。
在 2 型糖尿病患者中，单次尿 C 肽/肌酐比值是一种稳定、可重复的测量方法，与餐后刺激后的血清 C 肽相关性良好，即使存在中度肾功能损害。因此，尿 C 肽/肌酐比值在评估 2 型糖尿病的临床实践中具有潜在应用价值。
