Surrogate markers and predictors of endogenous insulin secretion in children and adolescents with type 1 diabetes.

BACKGROUND: No studies have examined endogenous insulin secretion in pediatric patients with type 1 diabetes in China using the gold-standard mixed-meal tolerance test. Because the latter is labor-intensive, we examined simpler surrogate markers of endogenous insulin secretion in Chinese youth, as previously reported for a European population. METHODS: Participants were 57 children and adolescents with type 1 diabetes aged 4.4-16.8 years (56% females). We performed 120-minute mixed-meal tolerance tests with serum C-peptide (CP) measurements every 30 minutes. Severe insulin deficiency (SID) was defined as CP peak < 0.2 nmol/L. Urine CP and creatinine levels were measured at 0 and 120 minutes. RESULTS: Twenty-five (44%) patients had SID. Fasting CP levels missed one case (96% sensitivity) with no false positives (100% specificity). While the 120-minute urine CP/creatinine had 100% sensitivity, it yielded markedly lower specificity (63%). Every 1-year increase in diabetes duration and 1-year decrease in age at diagnosis were associated with 37% (P < 0.001) and 20% (P = 0.005) reductions in serum CP area-under-the-curve, respectively. Thus, 86% of children aged < 5 years had SID compared to none among patients aged ≥ 11 years. CONCLUSIONS: Simple fasting CP measurements could be used to detect most SID cases in Chinese youth with type 1 diabetes. Fasting CP is a far more reliable measure of endogenous insulin secretion than the more commonly used insulin dose. Therefore, it could more precisely determine insulin secretory capacity to target those who could benefit, if treatments to preserve residual insulin secretion are developed.

[Prevalence and surgical status of cataract among adults aged 50 years or above in rural Jiangsu Province].

OBJECTIVE: To survey the prevalence, operative status, surgical coverage rate and social burden rate of cataract blindness among older adults aged 50 years or above in 2 typical counties (district) of Jiangsu Province, China in 2010. METHODS: Cluster sampling was used in randomly selected 12 867 individuals aged 50 years or above in 58 clusters in Funing County of Northern Jiangsu and Binhu District of Southern Jiangsu. Among them, 12 053 individuals received visual acuity and eye examinations (response rate 93.8%). Lens and cataract operative status were evaluated by slit-lamp biomicroscope. Data bank was established by Epidata3.0 Software. Statistical analyses were performed with Stata/SE Statistical Software, version 10.0. Confidence intervals and P values (significant at P < 0.05) for prevalence of cataract, surgical coverage rate of cataract, social burden rate and surgical outcomes of cataract blindness were calculated with adjustment for clustering effects and stratification associated with the sampling design. RESULTS: Among 12 503 individuals, there were 2208 cases of cataract with a prevalence of 18.3%. The prevalence of cataract was higher in the aged, female and lower-income persons (P < 0.05). Among 2208 cataract patients, cataract surgery was performed in 263 cases (11.9%). The surgical coverage rate of cataract was 59.7% and the social burden rate of cataract blindness 1.93%. The social burden rate of cataract blindness was higher in the aged persons (P < 0.01). In 357 eyes with cataract surgery, the rate of intraocular lens implantation was 85.7%. At Binhu, 71.0% of eyes with cataract surgery underwent phacoemulsification. At Funing, 73.6% of eyes underwent modern extra-capsular surgery respectively. Post-operative presenting and best corrected visual acuity over 0.7 was 11.2% and 19.6% of operated eyes respectively. The main causes of post-operative eyes with worse visual acuity (< 0.3) were post-capsular opacity and retinal disorders. CONCLUSION: Cataract is the most common and important eye disease that may lead into blindness and severe visual impairment among older adults aged 50 years or above. The coverage rate of cataract surgery is higher in Jiangsu province than in other provinces. The visual outcomes of surgery is less than ideal. An important task in blindness prevention of Jiangsu province still is the elimination of cataract blindness and the improvement of visual outcomes for cataract surgery in the future.