The Assessment of Risk Factors for Development of Disability in Children with Congenital Hypothyroidism in Uzbekistan within a Neonatal Screening

Abstract

The aim of this study was to detect the most significant risk factors leading to disability in children with congenital hypothyroidism (CH) in the autonomous Republic of Karakalpakstan (RK) during neonatal screening (NS). Methods and Results: We used data of patients with CH registered within NS in the RK in 1998-2019 by the Center for Screening of Mother and Child. To predict and calculate the most significant risk factors for disability in children with CH, we used the method of normalizing intensive indicators by E. Shigan, based on the Bayes theorem. The study recruited 111 patients with CH aged from 2 months to 20 years. Among the patients, there were 79(71.2%) girls and 32(28.8%) boys. Additionally, 34(30.6%) children with CH had been disabled since childhood. The lack of compensation after the start of treatment had the highest and most significant degree of disability risk (RR=6.39, 95% CI: 7.4-1.2). Among patients diagnosed outside of screening, disability developed 4.1 times more often than with the results of NS (RR=4.0, 95% CI: 1.1-10.6). In CH patients diagnosed outside of screening, “absence of reagents” was a significant factor increasing the risk of disability by 6.1 times (RR=6.1, 95% CI: 1.8-11.2). Such risk factors as “home delivery” and “parental refusal of the primary test” increased the risk of disability by 3.4 times (RR=3.4, 95% CI: 2.5-8.4) and 1.6 times (RR=2.4, 95% CI: 2.93-7.12), respectively. The possible errors or false-negative answers in the “normal” secondary test and the “normal” primary test increased the risk of disability by 3.3 times (RR=4.0, 95% CI: 3.2-10.7) and 2.4 times (RR=2.42, 95% CI: 2.93-7.12), respectively. Factors such as the “late response to retesting” (RR=0.82 95% CI: 0.65-0.54), “late awareness on the part of the medical staff” (RR=0.29, 95% CI: 0.27- 0.08), and "parental refusal of treatment" (RR=1.03, 95% CI: 0.81-0.84) showed less significance in patients' disability. The “starting treatment after 1 month” factor was 4.2 times more likely to result in disability than “starting treatment before 1 month” (RR=4.2, 95% CI: 4.5 -1.1). Cancellation of levothyroxine by parents for children up to 3 years of age and cancellation of treatment by parents after 3 years more likely resulted in disability by 1.4 times (RR=1.43, 95% CI: 1.4 -2.01) and 3.3 times (RR=3.33, 95% CI: 3.3-10.9), respectively. Conclusion: the most significant risk factors for the development of disability in children with CH in the RK were (in descending order): no compensation after starting treatment, no reagents for screening, starting treatment after 1 year, diagnostics outside of screening, cancellation of L-T4 by parents before and after age 3 years, false-negative secondary TSH test, false-negative primary test, parents refusing the primary test, and childbirth at home.

Keywords

• risk factors
• congenital hypothyroidism
• disability
• neonatal screening