In this study, we describe the burden of dermatological and subcutaneous diseases on the Thai population of Ubonratchathani, using real-world health care service data. The prevalence of dermatological diseases was as high as 7% and varied across gender, age group, and geographic regions. Dermatitis, bacterial skin infection and urticaria were the most common skin diseases. The rate of DALYs attributed to dermatologists was 26,125, which is generally higher in males than in females. Cellulitis, decubitus ulcers, and contact dermatitis were the main causes of the rate of DALYs in this population.
Skin diseases have been common worldwide, although overall prevalence has varied widely across different countries. The prevalence of dermatological diseases in this study was approximately 7%. This was much lower than the prevalence rate reported in other population survey studies, where the overall prevalence was reported as 15% and 27% in Bangladesh and European countries, respectively.17, 18. This discrepancy can be explained by the fact that the Bangladesh study was conducted in one rural community without systematic sampling of participants, and therefore they were subject to biased selection—those with symptoms and signs of skin disease likely to participate, and thus a high prevalence. In addition, a population survey in European countries described a lifetime prevalence, while our study reported the prevalence of any skin diseases diagnosed and recorded in electronic health records in 2018. Differences in study settings, methods of calculation, and definitions may make it difficult to compare the prevalence of skin diseases. across studies.
Comparing the prevalence of skin diseases is more difficult when considering the type or types of skin diseases. Based on the 2010 Global Burden of Disease of Dermatology, fungal skin diseases, acne and other skin and subcutaneous diseases were among the 10 most prevalent diseases globally.2. Dermatitis has been one of the most prevalent skin diseases worldwide, and the prevalence of dermatitis and its subtypes has varied among the population. Dermatitis forms 21-32% of all skin diseases10, 17, 19, 20. While atopic dermatitis accounts for most cases of dermatitis in developed countries6, 18,21And the2223Contact dermatitis accounted for most cases of dermatitis in our study and some European countries18. Skin infection from scabies was common in developing countries10, 17, 19, but rarely occurs in developed countries. For example, the prevalence of scabies was as high as 15% among the population of Pakistan10while the figure was less than 1% in this Thai population and most developed countries2. Interestingly, warts and acne topped the list of the most common skin diseases in European countries18while it was less prevalent in developing countries2. These differences may indicate real differences in the pattern of skin diseases between countries and geographic regions or simply reflect the different age groups of study participants and methods for obtaining prevalence estimates.
Dermatological diseases contribute to the large disease burden, and this is said to vary by type of skin disease and vary across global regions and countries. Consistent with the 2017 Global Burden of Disease and other previous population-specific studies, our study showed that dermatitis was among the leading causes of DALYs, although there were different burdens due to its different subtypes. For example, atopic dermatitis has dominated the burden of all dermatitis in developed countries24. While contact dermatitis topped the list of dermatitis in our study. While cellulitis contributed to 45% of DALYs due to dermatological conditions in this study, it resulted in only 1% of total DALYs from dermatological conditions globally.6. This discrepancy may reflect the contribution of DALYs to the higher prevalence of contact dermatitis and the higher early mortality from cellulitis in the Thai population compared to other populations. This relatively high burden of cellulitis and subcutaneous bacterial infection in Thailand may simply reflect the lifestyle of the people in the region where traditional farming has remained prevalent with the disproportionately high use of agricultural chemicals. This may also indicate potential differences in health care service systems and health care quality between countries. Besides, this may be explained by differences between these studies in the quality and completeness of data on prognosis, relevant consequences and cause-specific mortality used to calculate DALYs. Our findings on the top five causes of life-deficit infection, life-years lost, and rate of DALYs can be used to inform policy decision about allocating resources to focus more on the prevention of diseases that were the main causes of DALYs, such as dermatitis, and on the prevention and reduction of of complications and deaths. Related to the main causes of lost blood transfusion, such as cellulitis and decubitus ulcers. This informed policy decision will be critical in order to effectively reduce the rate of DALYs in resource-limited countries such as Thailand.
Gender differences in DALYs due to dermatological conditions exist in many populations. This may be attributed to gender differences in the pattern of skin disease burden. Compatible with previous studies2,6, our study found that YLLs constitute a higher relative contribution to DALYs in men than in women. Men may be more likely to develop fatal skin diseases such as skin cancer, cellulitis, and other serious skin infections, while women may be more likely to develop non-fatal skin diseases such as dermatitis, pruritus, and urticaria. Interestingly, while the 2017 World Burden of Dermatology and 2010 Global Burden of Dermatology reports indicated that women have a greater overall burden of dermatological and subcutaneous diseases than men.2Our study showed opposite results. This may reflect true differences in patterns of disease burden from cutaneous disorders in the Thai and other populations, or may be explained by a difference in data sources and methods for calculating disease burden indices.
Skin cancers contribute to a significant burden of skin diseases, albeit with disproportionate contributions from different skin cancers in different countries. Whereas non-melanoma skin cancers (both basal and squamous cell carcinomas) were the most common cutaneous malignancies in many Caucasian and Asian populations.25And the2627, our study showed different results with the predominant malignant melanoma in this Thai population. When considering DALYs, our study is consistent with several previous studies indicating that non-melanoma skin cancers cause a greater disease burden than malignant melanomas. According to the 2011 Australia Burden of Cancer Report28, the disease burden measured as DALYs for skin cancers in Australia was significant, with melanomas ranking No. 5 and 9 as DALYs among all-site cancers in males and females, respectively. However, this report does not describe the rate of DALYs for melanoma and other skin cancers in relation to other skin diseases. While skin cancers were ranked among the top 6-7 contributors to DALYs of skin diseases for both males and females in this Thai population, they were not among the top ten causes of DALYs for both sexes in Mexico.29. The discrepancy in the burden of skin cancers could be explained by differences between countries in climate, sun exposure, and protective behaviors, or that Thais may have a skin type that protects them from UVB radiation compared to other Caucasians and Asians.26. It could be due to the disproportionately high incidence of skin cancer in the fair-skinned population24,30as well as the difference between countries in the health care system and the quality of health care that can affect the mortality of patients with melanoma, and thus the years of life lost.
Consistent with the methods adopted in the WHO 2020 Report on Global Health Estimates31, the prevalence-based approach to calculating DALYs does not require data on disease duration and is not significantly affected by the manner in which the discount rate is applied; However, this approach may lead to confusion as different methods are used to calculate YLDs and YLLs and YLDs for diseases of short duration can be underestimated.32. In contrast, in the incidence-based approach, YLLs and LLLs are continually measured, but data on disease duration are primarily required to account for and incorporate morbidities is relatively challenging. While the occurrence-based approach is more useful for informing policies or interventions focused on disease prevention, we have used the simpler prevalence-based approach because it provides information on the impact of specific diseases on economic productivity at a given time.
This study was among the first to examine the prevalence and burden of skin diseases as measured as DALYs in people of all ages in developing countries, using real-world health care service and mortality data and standard computation techniques. However, our study had some limitations. First, diagnoses of dermatological and subcutaneous diseases based on relevant ICD-10 codes from electronic health records did not include data on disease severity. This could have altered the estimate of disability-adjusted life years (DALYs) in our study. However, this may at least represent the burden in real world conditions. Our study used mortality derived from NHSO data because it most likely reflects all-cause, age- and sex-related mortality in this contemporary Thai population. It is possible that this may not really represent the cause-specific mortality of the dermatological disease of interest. This may also change the estimates of YLLs and DALYs in our study compared to those calculated using estimates of global disease burden. Besides, the current ICD-10 coding system did not allow separate ICD codes for squamous and basal cell carcinomas. Applying the mean weight of disability for squamous cell carcinoma to account for life years lost and rate of DALYs for patients with either squamous cell carcinoma or basal cell carcinoma would underestimate these measures of disease burden. However, sensitivity analysis using the mean weight of disability for basal cell carcinoma would reflect the highest possible estimates of disease burden for both diseases. Additionally, dermatology has been diagnosed by various health professionals from primary care nurses and medical practitioners to class tertiary healthcare professionals and dermatologists. Therefore, there may be uncertainty about the accuracy and completeness of the diagnostic information. Of particular note is that the number of cases diagnosed with acne and molluscum contagiosum was very small and may have been underestimated. This may be because most cases of these diagnoses, especially acne vulgaris, are not reimbursed by all types of National Health Insurance because they are considered aesthetic care. Hence, most patients seek care from over-the-counter treatment and private cosmetic and cosmetic clinics, which has been and is expected to be one of the fastest growing industries in Thailand.33. Since the data used in our analyzes did not include private and over-the-counter healthcare services, this likely affected our YLD estimates. However, all hospital diagnoses were routinely checked and coded by a trained programmer and then validated by the NHSO. Therefore, this verification method was likely to accurately capture the diagnoses and burden of dermatology in real-world clinical practices. A validation study may also be needed to check the accuracy of a dermatological diagnosis. Besides, it is important to acknowledge that estimates of DALYs based on the prevalence-based approach in our study may differ from those of the incidence-based approach. Finally, since our study was based on data from mixed urban and rural communities in Thailand, the generalizability of our results to other populations and countries may be limited.