Keywords
leprosy - biomedical technology - disability evaluation
Introduction
Leprosy is a chronic infectious disease of compulsory notification, caused by Mycobacterium leprae and characterized by peripheral neuropathy. In its evolution, especially in patients
not adequately treated, leprosy can evolve with different skin and neural lesions,
which can result in mutilations and different degrees of functional disability.[1] The Hansen bacillus presents tropism by the peripheral nerve, mainly by Schwann
cell. The degeneration of nerve fibers, leading to a mixed neuropathy, which compromises
sensory, motor, and autonomic nerve fibers. Neuropathic pain and neural thickening
are consequent clinical manifestations, occurring in 45.8% of patients.[2]
If not addressed properly, neuromotor dysfunction will result in functional deficit
in one or more segments of the body, known as leprosy-induced disabilities. Timely
diagnosis and treatment are important actions for the prevention of disabilities.
It is important to highlight that frequent anesthetic skin lesions are absent in the
pure neuritic form of the disease, which can also lead to disability due to dysfunction
of some nerve, which can occur in up to 60% of cases with neural impairment.[2]
The proportion of new leprosy cases diagnosed with grade 2 disability is an important
indicator for assessing late diagnosis of the disease.[3] In 2015, of 14,000 new cases of the disease diagnosed worldwide, 12% already had
a grade 2 disability. Brazil was the country that contributed the most to this proportion.[4] This disability is identified by simplified neurological evaluation (SNE), considered
as a reference for its diagnosis.[5]
[6]
[7] Simplified neurological evaluation is classified as grade 0 (zero), when there is
no evidence of neural involvement in the eyes, hands, or feet; grade 1 if there is
decreased or loss of sensitivity in any segment of the body; and grade 2 when there
is presence of lagoftalmo, disabilities and deformities, claws, bone resorption, loss
of hands and/or feet, loss of vision, among others.[8]
For decades, public policies for the diagnosis of leprosy have focused on the search
for dermatological signs rather than neurological symptoms.[9] The identification of peripheral nerve disorder is important to guide the regular
practice of self-care and relevant intervention.[10] Although it is apparently simple to investigate, SNE requires great skill from the
professional for its execution. The complete examination recommended by World Health
Organization (WHO) requires time and patience from the examiner and the patient, in
addition to the ability to perform the proposed techniques. Lack of this ability may
result in a delay in the diagnosis of disability.[11] This justifies the need for simple, easy-to-apply resources that do not require
a high degree of experience to track patients at an early stage of functional disability.
The disabilities of arm, shoulder, and hand (DASH) is an instrument that assesses
both symptoms and upper limb function from the patient's perspective. It is a questionnaire
that assesses the upper limb as a functional unit of the individual, regardless of
the pathology or even its location.[12] It can also point to dysfunction of other organic segments or systems, whose positive
predictive value reached 75%.[13] Through 30 questions, the DASH instrument assesses the degree of difficulty in performing
different physical activities using the the upper limbs, including activity-related
pain, tingling, weakness, stiffness, and the impact of this difficulty on social activities,
work, sleep, and self-image.[13]
[14]
[15] Due to the DASH questionnaire being extensive, another instrument was later proposed,
being simpler and more widely applied. This new questionnaire, called QuickDASH, has
already been translated and validated for Portuguese, and it is considered reliable
when used in patients with traumatic and non-traumatic diseases.[16] The instrument consists of 11 questions with 5 answer options scored on a Likert
scale ([Box 1]).[17] If at least 10 of the 11 items are answered, the points are added up to form a raw
score and then converted to a range from 0 to 100 points. To do this, subtract a point
from the sum of the answers and multiply the result by 25.[17]
[18] The higher the score, the higher the functional deficiency.
Considering the need to identify the functional disability caused by leprosy early,
as well as the lack of simple resources for its diagnosis, the present study aimed
to validate the QuickDASH questionnaire as a tool to be used by any health professional
to screen for functional disability presented by leprosy patients.
Materials and Method
This is a validation study of a diagnostic test conducted in a sample of 156 leprosy
patients, treated or under treatment, and in clinical follow-up at the infectious
diseases outpatient clinic of Hospital Universitário Júlio Müller (HUJM), located
in Cuiabá, MT. It is a reference service for the diagnosis and treatment of leprosy
in the state of Mato Grosso. The sample was convenient, with sequential intake of
patients and with adequate size to represent the target population.[19]
Only patients over 18 years of age and who agreed to participate in the study were
included after signing a free and informed consent form. Patients previously submitted
to neurotic or other orthopedic alteration due to leprosy were not included. The initial
clinical evaluation was performed by two examiners (authors B. P. A. and M. M. F.),
independently. Patients with agreement in these two clinical evaluations were included
in the analysis. Then, a SNE was conducted, and the QuickDASH instrument was applied,
originally proposed to be self-answered, but, in this study, it was applied in the
form of an interview, due to low schooling of the patients.
The data were tabulated and described in their absolute and relative frequencies or
in their statistical summaries in the Stata version 12.0 software (StataCorp, College
Station, TX, USA). Using as reference the results of the SNE (gold standard) and establishing
as 0 the absence and 1 the presence of some degree of functional disability identified
in the patient, sensitivity, specificity, predictive values, and accuracy of the QuickDASH
for the diagnosis of functional disability were determined. In addition, to evaluate
the discriminating power of the QuickDASH instrument for groups with and without functional
disability due to leprosy, a receiver operating characteristic (ROC) curve was represented
graphically.
The validity of a diagnostic resource is the ability of a test to discriminate between
the presence and absence of the target condition, and it can be quantified by means
of diagnostic accuracy measures, such as sensitivity, specificity, predictive values,
and accuracy. For quantitative measurement resources, the analysis of the ROC curve
represents the most appropriate tool for the establishment of these parameters.[20]
The ROC analysis is a technique that assesses the ability of a diagnostic test to
discriminate between patients who have and those who do not have a particular disease.
The ROC curve is made by tracing the false positive rate on the “x” axis with the
true positive rate on the “y” axis to a set of threshold values. The discriminatory
capacity of a test can be calculated by the area under the ROC curve (AUC). An AUC
of 1.0 indicates perfect discrimination, while an AUC of 0.50 represents no discriminatory
power of the test. In clinical practice, an AUC ≥ 0.75 is generally considered clinically
useful as a diagnostic resource.[13]
After AUC determination, a QuickDASH cut-off point was identified by the Liu[21] method (2012), from which it is possible to diagnose, with satisfactory accuracy,
the true positive and negative scans for functional disability caused by leprosy.
This method identifies the value that produces the highest sensitivity and specificity
values, along with the lowest probability of random occurrence.[21]
The present study was approved by the Ethics and Research Committee of Hospital Universitário
Júlio Müller, under case number: 12777719.5.0000.5541.
Results
We studied 156 patients at different stages of clinical follow-up of leprosy, 82 (52.6%)
males and 74 (47.4%) females. Their ages ranged from 18 to 86 years, with a mean (SD)
of 49.6 (12.7) years and a higher frequency of patients between 40 and 60 years. Patients
from urban areas (82.6%), with manual or domestic occupation (60.0%), with family
income lower than 2 minimum wages (65.9%), and with low schooling (64.7%) ([Table 1]) predominated.
Table 1
|
Feature
|
|
n
|
%
|
|
Age group (years)
|
18–30
|
11
|
7.0
|
|
31–40
|
30
|
19.2
|
|
41–50
|
33
|
21.2
|
|
51–60
|
50
|
32.1
|
|
> 60
|
32
|
20.5
|
|
Sex
|
Male
|
82
|
52.6
|
|
Female
|
74
|
47.4
|
|
Occupation
|
Administrative
|
22
|
14.2
|
|
Heavy work
|
62
|
40.0
|
|
Housework
|
31
|
20.0
|
|
Trade
|
26
|
16.8
|
|
Health
|
14
|
9.0
|
|
Residence area
|
Rural
|
27
|
17.4
|
|
Urban
|
129
|
82.6
|
|
Family income (minimum wage)
|
< 1
|
22
|
14.1
|
|
1–2
|
84
|
53.8
|
|
2–3
|
19
|
12.2
|
|
≥ 3
|
31
|
19.9
|
|
Schooling (years)
|
0–8
|
79
|
50.6
|
|
8–9
|
22
|
14.1
|
|
9–12
|
33
|
21.2
|
|
≥ 12
|
22
|
14.1
|
|
Operational classification (n = 155)*
|
Multibacilar
|
127
|
81.9
|
|
Paucibacilar
|
28
|
18.1
|
|
Polychemotherapy
|
Current
|
92
|
59.0
|
|
Previous
|
64
|
41.0
|
|
Retratamento
|
Yes
|
30
|
19.2
|
|
No
|
126
|
80.8
|
The patients in the study were mostly classified as multibacillary (81.9%), 92 (59.0%)
of them currently being treated with multidrug treatment (MDT). Thirty (19.2%) patients
were receiving MDT for the second time ([Table 1]).
It was observed that 86 (55.5%) patients presented some functional deficit by SNE,
representing 140 dysfunctional manifestations, which were due to visual alterations
in 31 patients, upper limbs in 49 patients, and lower limbs in 60 patients, which
resulted in a final disability classification of 0, 1, and 2 for 70 (44.9%), 46 (29.5%),
and 40 (25.6%) patients, respectively ([Table 2]).
Table 2
|
Inability
|
|
n
|
%
|
|
Type*
|
Any deficit
|
86
|
55.5
|
|
Visual
|
31
|
19.9
|
|
Upper limbs
|
49
|
31.4
|
|
Lower limbs
|
60
|
38.5
|
|
Degree of disability
|
0
|
70
|
44.9
|
|
1
|
46
|
29.5
|
|
2
|
40
|
25.6
|
The score obtained from patients after the application of the QuickDASH instrument
ranged from 0 to 81.8, with mean (SD) of 35.2 (24.1) points, median of 29.5 points.
About ⅓ of the patients (30.8%) had a score ≥ 50 points and a ¼ (25%) of them had
a score ≥ 54.5 ([Table 3]).
Table 3
|
Cutoff point
|
Sensitivity (%)
|
Specificity (%)
|
Positive predictive value (%)
|
Negative predictive value (%)
|
Accuracy (%)
|
|
15.0
|
87.2
|
42.0
|
65.2
|
72.5
|
67.1
|
|
20.0
|
84.9
|
46.4
|
66.4
|
71.1
|
67.7
|
|
25.0
|
77.9
|
58.0
|
69.8
|
67.8
|
69.0
|
|
30.0
|
72.1
|
68.1
|
73.8
|
66.2
|
70.3
|
|
35.0
|
66.3
|
75.4
|
77.0
|
64.2
|
70.3
|
|
40.0
|
59.3
|
79.7
|
78.5
|
61.1
|
68.4
|
|
45.0
|
57.0
|
82.6
|
80.6
|
60.6
|
68.4
|
The ROC curve created according to the QuickDASH score for discrimination of patients
with and without functional deficit shows that the AUC of 0.76 represents the accuracy
(76.0%) of this instrument for the diagnosis of functional disability caused by leprosy
([Fig. 1]). By Liu's method[21] (2012), the QuickDASH cutoff was estimated at 32.2 points, whose sensitivity and
specificity were 66% and 75%, respectively, with accuracy of 71%. However, the analysis
of the validity of different levels of the QuickDASH score showed that the cutoff
of 30 points resulted in a better balance between sensitivity (72.1%) and specificity
(68.1%), with accuracy of 70.3%, as well as positive and negative predictive values
of 73.8% and 66.2%, respectively ([Table 3]).
Fig. 1 ROC curve of the Quick-DASH score values for diagnosis of functional disability of
leprosy patients.
Discussion
In the present study, it was possible to demonstrate that the QuickDASH instrument
was sensitive, specific, and accurate to track patients suspected of functional disability.
It is a diagnostic resource of simple and fast application, already validated in portuguese
for the diagnosis of functional deficit consequent to several other injuries and without
any additional cost for its application. In addition, the positive predictive value
of a score higher than 30 in the QuickDASH instrunment was also high, to indicate
those patients most in need of referral to a higher level of complexity. This finding
demonstrates that the QuickDASH instrument, which can be applied by any health professional,
may contribute to a timelier identification of leprosy functional disabilities.
The frequency of patients who presented any type of functional deficit by the SNE
(55.5%), whether visual, upper, or lower limb, was high. This finding can be justified
by its performance having taken place in a reference center, where more complex cases
are referred to, and the sample includes individuals already treated and in retreatment
(19.2%). However, it is important to consider that, every year, around 47,000 new
leprosy cases are recorded in Brazil, of which 23.3% have disability grades I and
II and may reach up to 70% on the date of diagnosis.[23]
It was found that most patients in the study had sociodemographic characteristics
common to the general population of leprosy patients. The most frequent ones being
onset in adulthood, proportional balance between genders, occupations that require
physical exertion, residing in urban areas, low schooling, and precarious family income.
This sociodemographic profile has already been observed by several authors, even in
population-based studies.[24]
Early diagnosis is essential to prevent functional disability and to decrease the
chain of transmission of the disease. It can be inferred that the frequency of functional
disability caused by leprosy at the time of its diagnosis is a marker of the quality
of health care work. Initial treatments of the disease for patients with grade-2 disability
mean delay in diagnosis and inefficiency of screening made by the services. Some factors
are widely known as causes of this delay, such as late patient demand, difficulty
in accessing health services, and lack of specific training by health professionals.
On the latter, it is known that the quality of leprosy control actions performed by
health professionals produces effects in all indicator's disease monitoring.[25] Therefore, the importance of permanent training of professionals who care for leprosy
patients is unquestionable. Diagnostic resources that are simple and of rapid applicationbecome
fundamental to contribute to coping with this important health problem.
The satisfactory performance of the QuickDASH instrument for screening functional
disability in leprosy patients was demonstrated in this study when the result of the
instrument reached 30 points, with the correct classification (accuracy) of patients
in 71% of cases. Even though it is a proposed instrument for functional evaluation
of the upper body segment, the QuickDASH instrument proved sensitive in the screening
of other health conditions, such as insomnia, depression, rheumatoid arthritis, and
postoperative pain.[26]
[27]
[28] Because leprosy affects more than one body segment simultaneously and in different
proportions or stages, the instrument may be able to detect changes that are taking
place in various sites in addition to the upper limbs.
Studies state that an accuracy ≥ 70% in the ROC curve should be considered appropriate
to indicate tests for the screening of health conditions.[29] There are several circumstances in which a test can be chosen for its high sensitivity,
even having low specificity (or vice versa), if it is cheaper, simple to perform,
or more accessible.[20] Such tests are generally used for the screening of various health conditions.
In Brazil, technology policies for health have been implemented since 1994.[30] Health tools are being increasingly used and can be any type of electronic device,
monitoring system, or an instrument that can be applied by health professionals in
clinical practice with the objective of characterizing, diagnosing, monitoring, or
improving the health status of individuals.[31] The main finding of the present study includes this policy, since it proposes a
simple and rapid application resource to be incorporated into primary care scenarios
or in the outpatient health care network. The use of this diagnostic screening feature
may contribute to the appropriate and timely referral of leprosy patients to confirm
their actual situation in relation to the functional disability caused by the disease.
Some limitations should be considered in the interpretation of the results of this
study. The inclusion of patients from a reference outpatient clinic may overestimate
the frequency of disabilities. Although a high prevalence of the event of interest
has an impact on the predictive value of diagnostic resources, this frequency measurement
does not interfere with the sensitivity or specificity and, consequently, has no effect
on the accuracy of the test.[29] Although the QuickDASH was originally extracted from the DASH instrument, which
is a resource focused on upper member evaluation, this instrument turned out to be
sensitive to screening for other pathologies such as insomnia, rheumatoid arthritis,
and postoperative pain.[26]
[27]
[28]
Conclusion
The QuickDASH showed good accuracy to track functional disability in leprosy patients,
which may be useful in clinical practice in order to identify patients who require
specialized referral for the prevention and treatment of this condition.
Box 1
|
Degree of dificulty in the performance
|
None
|
Little
|
Some
|
A lot
|
Incapable
|
|
1. To open a new or tightly closed bottle
|
1
|
2
|
3
|
4
|
5
|
|
2. To do heavy household chores (wash the floor)
|
1
|
2
|
3
|
4
|
5
|
|
3. to carry a shopping bag or a briefcase
|
1
|
2
|
3
|
4
|
5
|
|
4. To wash one's own back
|
1
|
2
|
3
|
4
|
5
|
|
5. To use a knife to cut food
|
1
|
2
|
3
|
4
|
5
|
|
6. To perform an activity that requires force (hammer, sickle, hoe)
|
1
|
2
|
3
|
4
|
5
|
|
Interference in everyday life
|
None
|
Little
|
Some
|
A lot
|
Total
|
|
7. To what extent have the above problems interfered with your social relationship
with family, neighbors, friends, and others
|
1
|
2
|
3
|
4
|
5
|
|
8. To what extent have the above problems interfered with your ability to work or
other tasks
|
1
|
2
|
3
|
4
|
5
|
|
Severity of symptoms in the last week
|
None
|
Little
|
Some
|
A lot
|
Extreme
|
|
9. Pain in the arm, shoulder, or hand
|
1
|
2
|
3
|
4
|
5
|
|
10. Numbness (tingling) in the arm, shoulder, or hand
|
1
|
2
|
3
|
4
|
5
|
|
11. Difficulty sleeping because of this pain
|
1
|
2
|
3
|
4
|
5
|
