Functioning and Hansen’s disease: evaluation of components of the International Classification of Functioning, Disability and Health (ICF)

In 2018 208,641 new cases of Hansen’s disease (HD) were diagnosed worldwide (new case detection rate 2.74/100,000 inhab.), of which 11,323 (5.43%) were severely disability, classified as physical grade 2 disability (G2D). In the same year, the rate of new HD cases with G2D per 1 million population was 1.5 (1). In Brazil, there were 28,660 new cases (new case detection rate 13.7/100,000 inhab.), 2,109 (7.35%) with G2D, making a rate of 10.08 cases with G2D per million inhab. (2).

HD is a neglected disease that compromises peripheral nerves and skin, therefore physical disabilities are frequent complications, indicators of late diagnosis, and can determine functional, psychological, emotional and social repercussions.

Taking as a reference the epidemiological indicators adopted by the World Health Organization (WHO), it can be seen that the epidemiological condition for leprosy in Brazil is highly endemic (3). In relation to global data, especially when there is a high proportion of G2D (due to the disease) among the general population, the severity of impairment and deformities becomes evident (2), as well as the data demonstrating the repercussions that the disabilities may have on the life of the person, including after completion of multidrug therapy (4).

Based on the model adopted by the International Classification of Functioning, Disability and Health (ICF), the understanding of "functioning" presupposes the extended evaluation of a person, in several domains, considering body functions and structures, activities, participation, environmental factors and personal factors (5). However, functioning results from the interaction of several contextual factors, and can be strongly determined by social stigma and discrimination (6), considered as environmental factors (5).

From this expanded perspective, with regard to disabilities, the Global Leprosy Strategy 2016-2020 has established, among its targets: (i) that no person under 15 years of age is diagnosed with G2D; (ii) that less than one case of G2D per million population be reduced; and (iii) that no country in the world has laws or legislation allowing discrimination due to HD (7). At the national level, in line with the Global Strategy, the Ministry of Health proposes, by 2022: (i) to reduce the total number of children with G2D by 23%, from 39 in 2018 to 30 in 2022; (ii) to reduce the G2D rate per million population by 12%, from 10.08/1 million inhabitants in 2018 to 8.83/1 million inhabitants in 2022; and (iii) to establish channels for the registration of discriminatory practices against persons affected by HD and their families (8).

In order to measure the status of physical disabilities, HD programmes classify them according to the standard established by WHO. With this tool, the components "Body functions" and "Body structures" are assessed. In it, structures such as eyes, hands and feet are considered, with a gradation of 0 to 2, where 0 indicates the absence of physical disabilities due to HD, 1 is equivalent to a decrease in protective sensitivity or a slight decrease in strength, without visible deformities, and 2 indicates the presence of visible deformities (9).

To broaden the scope of assessment tools, the SALSA Scale - Screening of Activity Limitation and Safety Awareness - is a multi-language validated tool, based on the ICF, intended to measure the "Activity" component (10). Through this tool, activity limitation and risk awareness are estimated from an individual perspective, categorized within a score of 10 to 80 points, from "no activity limitation" to "very severe limitation" (11).

Considering a situation in which the functioning is analyzed from a social perspective, differently from the "activity" which is individual, the "Participation" component of the ICF is measured by the Social Participation Scale. Also validated in brazilian portuguese, it provides a measure of the participation restriction in situations in which the person evaluated establishes a comparison between him/her and another chosen by him/her, with characteristics similar to his/her own in all aspects, except that he/she does not present the illness or impairment and, in the impossibility of indicating this person, a situation of a hypothetical individual with the characteristics described above should be used. The score can vary from 0 to 90 points, in a categorization from "no significant restriction" to "extreme restriction" (11, 12).

ICF recognizes that impairments can result in loss of socialization, but in another direction, a problem of performance or capacity, even in the absence of disability, can arise from a compromised social context, so that discrimination and/or stigma can affect functioning (5). With a view to approaching a multidimensional approach according to the ICF's model of functioning and disability, it is suggested that the quantitative evaluation of the "environmental factors" component be incorporated. For this purpose, a generic scale for stigma assessment - Explanatory Model Interview Catalogue - EMIC Stigma Scale (13) has gone through the process of cross-cultural adaptation to be used with people affected by HD in Brazil (14, 15). The scale is composed of 15 items, the result of which reaches a total value between 0 and 45 points, but without establishing a standardized categorization for the result, having for its interpretation the understanding that the higher the score reached, the higher the level of perceived stigma and self-stigma (16).

Considering the extent of commitment that HD can determine in a person's life and under the guidance of the model of functioning and disability adopted by WHO, the above instruments correspond to a summary of tools applicable to the HD condition at different levels of complexity, especially in the context of primary health-care, which instrumentalize the staff within the various points of the health-care network. It should be noted that timely case management involves monitoring the functioning components from the time of diagnosis, during the course of multidrug therapy (MDT) and follow-up after completion of MDT (17).