A total of 296 patients with a diagnosis of HFMD were included in the analysis. Of these, 120, 120, and 56 patients were from Shanghai, Zhengzhou, and Kunming, respectively. The characteristics of the enrolled patients and their guardians are presented in Table 1. In this cohort, 49.7% (147/296) of the patients were boys, and 50.3% (149/296) were girls. The mean (SD) age of the patients was 3.07 (1.50) years old. A total of 69.9% (207/296) of the guardians reported that they did not use any medical insurance, with the highest being for patients in Kunming (89.3%). A total of 73.6% of the guardians were female, and most of them were the mothers of the children (71.6%). The mean (SD) age of the guardians was 31.30 (5.48) years old, and most of them were married (97.6%). More than half of the guardians had received a university education or above (52.0%), and most of them worked in enterprises or were self-employed (53.9%). In terms of income, 35.1% of the guardians earned 20,000–30,000 CNY per month, and 38.9% earned 10,000–20,000 CNY per month. Almost all of the guardians were Han Chinese (97.0%), and nearly two-thirds of them were living in cities (63.5%) and were not religious (97.3%). The characteristics of the patients and their guardians statistically differed among the three regions except for the sex of the guardian (P = 0.117), marital status (P = 0.071), and religious status (P = 0.258).

The responses for each dimension of the Y-5L questionnaire at admission and discharge are presented in Table 2. At admission, the highest proportion of the respondents with problems was in the having pain or discomfort dimension (97.6%). For the mobility (walking about) (P = 0.009) and having pain or discomfort (P = 0.031) dimensions, there were significant differences among the three regions. Moreover, the patients and guardians from Shanghai had the highest proportion of reported problems in the mobility (walking about) dimension, while the children and guardians from Zhengzhou had the highest proportion of problems in the having pain or discomfort dimension. At discharge, the HRQOL of the patients improved significantly after treatment. For all samples, over half of respondents reported no problems in all dimensions (from 62.8 to 74.0%). There were significant differences in responses among the three regions in the dimensions of having pain or discomfort (P < 0.001) and feeling worried, sad, or unhappy (P < 0.001). In addition, the guardians from Kunming reported the fewest problems in these two dimensions.

Table 3 presents the Y-5L HUS and EQ-VAS scores of the children with HFMD in the three regions. Regardless of admission, discharge, and admission-and-discharge differences, the HUS and VAS score among the three regions were significantly different (P < 0.05). At admission, the mean (SD) HUS of the patients was 0.730 (0.140), and the patients from Shanghai had the lowest HUS (0.710). The mean (SD) VAS score of all respondents was 60.33 (16.52), and similarly, the children from Shanghai had the lowest score (57.38). At discharge, patients’ HUS and VAS scores both improved substantially, increasing to 0.920 (0.120) and 89.95 (11.88), respectively. The children from Kunming reported the highest HUS (0.950) and VAS score (96.95). For admission-and-discharge differences, the HUS improved by an average value of 0.180. In terms of regions, the HUS increased by 0.210, 0.150 and 0.200 in children from Shanghai, Zhengzhou, and Kunming, respectively. Similarly, the children from Shanghai reported the largest VAS score improvement (31.55).

On post hoc analysis, the HUS reported by the children from Shanghai and Zhengzhou were significantly different at admission (0.710 versus 0.750, P = 0.041) and at discharge (0.210 versus 0.150, P < 0.001). In addition, there were significant differences in VAS scores between patients from Shanghai and Kunming at admission (57.38 versus 72.05, P < 0.001) and at discharge (88.92 versus 96.95, P < 0.001). The change in the VAS score was also significant (31.55 versus 24.89, P < 0.020). When comparing the VAS score and HUS of children from Zhengzhou and Kunming, there were significant differences in the VAS score at admission (57.83 versus 72.05, P < 0.001), the VAS score at discharge (87.71 versus 96.95, P < 0.001), the HUS at discharge (0.900 versus 0.950, P = 0.034), and the change in the HUS before and after receiving treatment (0.150 versus 0.200, P = 0.003) (Table 3).

The cost of patients with HFMD is presented in Table 4. The mean (SD) total economic burden of HFMD was 5157 (2175) CNY per patient. The patients from Shanghai and Kunming reported the average highest (5491 CNY) and lowest total cost (3875 CNY), respectively. The mean (SD) hospitalization cost was 4037 (2434) CNY. The mean hospitalization cost was 4559 (2364) CNY, 4488 (2463) CNY and 1951 (1048) CNY in Shanghai, Zhengzhou, and Kunming, respectively. The mean length of stay was 5.2 (2.1) days, and the patients from Kunming reported the shortest hospitalization stays (4.4 days). However, the average hours of loss of work for guardians in Kunming (44.5 h) was approximately twice that of guardians in Shanghai (20.5 h) and Zhengzhou (20.7 h). Therefore, the guardians from Kunming reported the highest indirect cost (1887 CNY), followed by those from Zhengzhou (878 CNY) and Shanghai (872 CNY).

The results of the multiple linear regression model illustrating the association between the baseline HUS and sociodemographic variables are presented in Table 5. Compared with the patients covered by any medical insurance, those who paid all by themselves were associated with a significant reduction in the HUS by 0.04 (95% CI, − 0.07 to 0.00, P = 0.039). Compared with that for children from Shanghai, there was a significant increase in the HUS for patients from Zhengzhou (0.05, 0.01 to 0.08, P = 0.045) and Kunming (0.05, 0.00 to 0.10, P = 0.045).

For the change in the HUS at discharge, younger children had significantly lower HUS difference than older children. Compared with patients from Shanghai, there was a significant smaller reduction in HUS difference for patients from Zhengzhou. The same results were also found in the comparison of rural patients to city patients. Additionally, compared with children whose guardians worked in enterprises or were self-employed, the children whose guardians engaged in other professions involving government or institution employees, full-time stay-at-home parents or housewives, and farmers showed a significantly lower HUS difference (Table 5).

Similar regression models were performed to assess the association of the total cost and hospitalization costs with the sociodemographic characteristics (Table 6). The total cost was significantly associated with region, loss of work time, and length of stay, while the hospitalization cost of HFMD patients was significantly associated with region and length of stay.