Patient characteristics
Total of 285 574 patients attended to the respiratory outpatient department of the hospital during the 10-year study period. Preschool children aged < 7 years old accounted for 88.0% of all the children. The number of children aged 1 to < 4 years was twice of those aged < 1 years and 4 to < 7 years. Males accounted for 59.6% of the patient participants, 39.4% of the patients were covered by government insurance and 60.6% were self-finance. Respiratory specialist clinic provided medical service for 46.5% patients mainly with special respiratory diseases. The doctors with associate professor position or above provided medical service for 52.3% patients in the expert-clinic. The median and the 25th and the 75th percentiles of visits per children were 1 and (1, 3), and the number of visits had no significant difference between the patients covered by government insurance and those who were self-finance [1(1, 3) vs. 1(1, 2)]. (Table 1)
Overall trend in ROVs
During the 10-year study period, the overall ROVs were 698 054, increasing from 28329 visits in 2009 to 101 419 visits in 2018 with an AAGR of 15.2% (Fig. 2).
Age trends in ROVs
Fig. 3 displayed the change of the proportions and the trends in number of visits at different age groups through the years, respectively. For children aged < 1 year, the proportion of total visits declined from 24.3% in 2013 to 17.4% in 2018 (P<0.001) and the annual visits increased over time with an AAGR of 14.7% (P<0.001). For children aged 1 to < 4 years, they remained stable 43% of total visits and increased with an AAGR of 14.9%. For children aged 4 to < 7 years, the proportion of total visits increased from 22.8% to 28.4% (P<0.001) and the AAGR appeared the highest of 16.9% among all age groups (P<0.001). For children aged 7 to < 12 years and 12 to < 18 years, they accounted for 9% and 1% of total visits and the AAGR increased slowly from 13.1% to 13.8%, respectively.
Gender trends in ROVs
For male children, they accounted for 60.6% of total visits, from 62.9% in 2009 to 59.2% in 2018, with an AAGR of 14.4%. For female children, the proportion to total visits varied from 37.1% in 2009 to 40.8% in 2018 with an AAGR of 16.4%.
Overall diagnoses distribution
During the past 10 years, 23 different diagnoses categories were identified for all ROVs. Bronchitis was the most commonly identified diagnosis with 190 088 (27.6%) of total visits, followed by pneumonia (126 887, 18.5%), pneumonia affecting other systems (126 469, 18.4%), asthma and status asthmaticus (73 443, 10.7%), vasomotor and allergic rhinitis (62 951, 9.2%), other lower respiratory infections (42 353, 6.2%), and other respiratory diseases (65261, 9.4%). The distributions of all the identified diagnoses were shown in Fig. 4.
Gender- and age-specific trends in proportion of diagnoses
Fig. 5 showed the change of proportions of the selected three main diagnoses, bronchitis, pneumonia, asthma and status asthmaticus, stratified by gender.
For male children, the proportion of bronchitis in all ages declined from 34.8% in 2009 to 25.6% in 2018. In different age categories, the proportion of bronchitis for children aged < 1year declined from 34.5% to 24.8%, aged 1 to < 4 years 37.1% to 27.9%, aged 4 to < 7 years 34.5% to 25.7%, aged 7 to < 12 years 33.4% to 19.5%, and aged 12 to < 18 years 26.1% to 11.3% (Fig. 5-A). For female children, the proportion of bronchitis in all ages and age-specific categories showed the similar decline through the years (Fig. 5-B).
For male children diagnosed pneumonia, the proportion of the disease in all ages increased from 13.0% in 2009 to 21.7% in 2018. Comparing the different age categories, children aged < 1 year and 1 to < 4 years accounted for larger proportion of pneumonia (13.6% and 11.96% in 2009; and 22.1% and 22.4% in 2018) than the older age categories, for example, male children aged 4 to < 7 years, 7 < 12 years, and 12 to < 18 years (4.8%, 8.8%, and 7.4% in 2009; and 12.9%, 13.2%, and 12.7% in 2018) (Fig. 5-C). For female children, the proportion of pneumonia showed the similar increasing trend through the years (Fig. 5-D).
For male children diagnosed asthma and status asthmaticus, the proportion of the diagnoses accounting for all visits decreased from 16.1% in 2009 to 10.3% in 2015, and then increased again to 11.5% in 2018. In age-stratified analysis for male children, the diagnoses (for example in 2009 and 2018) accounted for larger proportion in elder strata (35.1% and 28.6%, and 24.9% and 22.7% for 12 to < 18 years and 7 to < 12 years, respectively), while accounted for smaller proportion in younger strata (20.4% and 17.3%, 15.9% and 12.1%, and 12.9% and 8.2% for 4 to < 7 years, < 1 year, and 1 to < 4 years, respectively) (Fig. 5-E). For female children, the proportion of asthma was lower than the male children at every age categories with similar change through the years. For example, 17.4% female children aged 7 to < 12 years were diagnosed asthma in 2009 and 13.6% in 2018, which were lower than those of the male children in the same age category (24.9% in 2009; 22.7% in 2018, respectively, P<0.001) (Fig. 5-F).
Gender- and age-specific trends in visits of diagnoses
Table 2 showed the trends of the number of visits by respiratory diagnoses. For children diagnosed with bronchitis, the females had higher AAGR compared to the males in all age categories (14.6% vs. 10.39 for aged < 1 year, 12.9% vs. 10.8% for aged 1 to < 4 years, 15.5% vs. 12.4% for aged 4 to < 7 years, 7.4% vs. 6.0% for aged 7 to < 12 years, and 6.8% vs. 2.5% for aged 12 to < 18 year). Children aged < 7 years had higher AAGR than the older children for both the males and females (P for trend <0.001).
For children diagnosed with pneumonia, they had nearly two fold AAGR compared to the children diagnosed with bronchitis and asthma. Female children had also higher AAGR than the males in all age categories, and the AAGR varied little between different age categories.
For children diagnosed with asthma and status asthmaticus, the AAGR was similar to that of the children with bronchitis, while it was higher than that of children with bronchitis aged >= 7 years. For each age category, female children with asthma had higher AAGR compared to the male children (Ps <0.001).