Rheumatology 2009;48:1111–1113
Advance Access publication 6 July 2009
doi:10.1093/rheumatology/kep178
Presentation and severity of rheumatoid arthritis at
diagnosis in Senegal
Souhaı̈bou Ndongo1, Fernando K. Lekpa1, Mamadou M. Ka1, Nafi Ndiaye1 and Thérèse M. Diop1
Objective. Early effective treatment slows structural damage in RA but requires an early diagnosis. Our objective was to determine
symptoms duration and presentation patterns of RA at diagnosis in Senegal.
Methods. We conducted a cross-sectional study over a 2-year period (from March 2006 to February 2008) at the rheumatology clinic of the
Le Dantec teaching hospital in Dakar, Senegal. Consecutive new patients who met ACR criteria for RA were included.
Results. We included 100 patients, 88 females and 12 males, with a mean age of 40.3 15.5 years and a mean symptoms duration of
54 months. One-fourth of the patients had a positive family history. Pain was the main reason for the rheumatology clinic visit. Mean pain
score was 64.3 mm on a 100-mm visual analogue scale. Nocturnal arousals were reported by 69% of the patients and morning stiffness for
>1 h by 74%. The tender and swollen joint counts were 10 or higher in 87% and 36% of the patients, respectively, and the mean disease
activity score on 28 joints (DAS28) was 6.49 1.34. Sicca syndrome (n ¼ 13) and rheumatoid nodules (n ¼ 3) were the main extra-articular
manifestations. Laboratory evidence of inflammation was found in 87% and RF in 78% of the patients. Antibodies to cyclic citrullinated
peptides (anti-CCPs) were detected in 26 of the 29 patients. Radiographical lesions were visible in 56% of the patients; mean modified
Sharp score was 21.76 47.74.
Conclusion. The diagnosis of RA is delayed in Senegal, and the disease is highly active at diagnosis, although 44 patients have no erosions,
and extra-articular manifestations are rare.
KEY
WORDS:
Rheumatoid arthritis, Severity, Disease activity, Sub-Saharan Africa, Senegal.
Written informed consent was obtained from all patients prior
to study inclusion, and approval of the appropriate ethics committee was obtained (le comité d’éthique de la faculté de médecine
de Dakar). For each patient, the following data were recorded:
age, sex, time since symptom onset, previous physician visits for
the symptoms, medical history, tender and swollen joint counts,
pain score on a visual analogue scale (VAS), whether nocturnal
awakenings occurred, morning stiffness duration, extra-articular
manifestations, laboratory markers for inflammation (ESR, serum
CRP and blood cell counts), autoantibodies [RFs and antibodies
to cyclic citrullinated peptides (anti-CCP)], modified Sharp score
[11], the disease activity score on 28 joints (DAS28) and treatment
at study inclusion.
EpiInfo software 6.0 (Centers for Disease Control, Atlanta,
GA, USA) was used to compute descriptive statistics. Values are
reported as medians (range) except when stated otherwise.
Introduction
RA is a chronic inflammatory disease of connective tissue that
predominantly affects the SM. Function-threatening joint lesions
and life-threatening extra-articular manifestations may develop.
RA is the most common chronic inflammatory joint disease and
occurs throughout the world, in all ethnic groups, with a prevalence that ranges from 0.3 to 1.2% [1]. Many studies suggest a
low prevalence of RA in sub-Saharan Africa and decreased disease severity among blacks living in Africa or elsewhere compared
with other ethnic groups [2–6]. These findings may be ascribable
to the low prevalence of the shared epitope HLA-DRB1 [7].
Identifying disease severity differences across ethnic groups is
important as such differences may provide hypotheses for genetic
studies aimed at elucidating the pathophysiology of RA.
There is a firm evidence that early effective treatment can slow
or stop joint damage progression in patients with RA [8, 9].
Therefore, the diagnosis must be made early, which requires
patient referral to a rheumatologist at symptom onset. Early
referral requires both good awareness of RA symptoms among
primary healthcare providers and availability of rheumatologists.
In Senegal, a country with a population of 11 million, there are
only five rheumatologists, suggesting that the early diagnosis
of RA may be difficult to achieve. The objectives of this study
were to determine symptom duration and to describe presenting
symptoms at the diagnosis of RA in Senegal.
Results
Demographical data
During the study period, 100 patients were diagnosed with RA at
our rheumatology clinic and 510 patients with previously diagnosed RA were seen. The 100 new patients had a mean age of
40.3 15.5 years. There were 88 women and 12 men (Table 1).
One-fourth of the patients reported inflammatory joint disease in
at least one family member; the exact diagnoses were not determined. One patient was homozygous and five were heterozygous
for haemoglobin S.
Patients and methods
We conducted a cross-sectional study over a 2-year period (from
March 2006 to February 2008) at the rheumatology clinic of the
Le Dantec teaching hospital in Dakar, Senegal. Consecutive new
patients who met ACR criteria for RA [10] were included.
Clinical data
The mean time from joint symptom onset to the diagnosis of
RA was 54 (range 1–360) months. Referral and diagnosis
occurred within the first year of symptom onset in only 12 of
the 100 patients. Half of the patients were evaluated by two or
more physicians before coming to our rheumatology clinic.
Joint pain was the main reason for the clinic visit. The mean
VAS pain score was 64.3 mm. Nocturnal arousals, which ranged
from a single awakening per night to complete sleeplessness, were
1
Department of Internal Medicine, Aristide Le Dantec Teaching Hospital, Dakar,
Senegal.
Submitted 22 April 2009; revised version accepted 27 May 2009.
Correspondence to: Souhaı̈bou Ndongo, Clinique médicale I - H.A.L.D - Dakar,
BP: 6034 Dakar étoile, Senegal. E-mail: [email protected]
1111
ß The Author 2009. Published by Oxford University Press on behalf of the British Society for Rheumatology. All rights reserved. For Permissions, please email: [email protected]
Souhaı̈bou Ndongo et al.
1112
reported by 69% of the patients and morning stiffness of >1 h
duration by 74% of the patients.
The tender joint count was 10 or higher in 74% of the patients.
One or more swollen joints were noted in 87% of the patients and
the swollen joint count was 10 or higher in 36% of the patients.
The mean DAS28 score was 6.5 1.3. Sicca syndrome was the
most common extra-articular manifestation, with 13 patients.
Rheumatoid nodules were noted in three patients, fever in two
patients, enlarged peripheral lymph nodes in two patients, a
decline in general health in one patient, myalgia in one patient
and tarsal tunnel syndrome in one patient.
Laboratory data
Laboratory tests showed evidence of inflammation in 87% of the
patients. The mean serum CRP level was 16 (1–96) mg/l and the
mean ESR was 49 (4–120) mm/h. Inflammatory anaemia was
found in 48% of the patients.
Tests for RFs were positive in 78 (78%) patients, of whom
19 had a positive latex test and a negative Waaler–Rose test and
59 had positive results by both tests. Due to the limited resources,
anti-CCP antibodies were tested in only 29 patients, of whom
26 (90%) had positive titres.
Radiographical data
Radiographs showed structural damage in 56% of the patients.
The mean modified Sharp score in these 56 patients was
21.8 47.7.
Treatments used at the diagnosis of RA
Of the 100 patients, 47 were taking NSAIDs, 37 analgesics,
19 glucocorticoids, 18 benzathine benzylpenicillin (for a mistaken
diagnosis of rheumatic fever) and 6 traditional treatments
TABLE 1. Main features at the diagnosis of RA in 100 black patients in Senegal
Features
Age, median (range), years
40.5 (17–81)
Females/males, n
88/12
Time from symptom onset to diagnosis, median (range), months 24 (1–360)
VAS pain score, median (range), mm
5.5 (0–9)
Tender joint count, median (range), number
24 (2–28)
Swollen joint count, median (range), number
4 (0–24)
Haemoglobin level, median (range), g/dl
11.6 (5.9–16.1)
ESR, median (range), mm/h
44.5 (4–120)
CRP, median (range), mg/dl
12 (0–96)
DAS28, median (range), points
6.8 (3.6–8.3)
RF, latex, median (range), IU/l
32 (0–256)
RF, Waaler-Rose, median (range), IU/l
29 (0–800)
60 (0–162)
Anti-CCPa, median (range), IU/l
Modified Sharp index, median (range), points
16 (0–247)
a
Anti-CCP antibodies were assayed in only 29 of the 100 patients.
including scarification for synovitis (Fig. 1) or decoctions. None
was taking DMARDs.
Discussion
This study provides information on symptom duration and
presenting symptoms at the diagnosis of RA in Senegalese patients
naive to DMARDs. The long symptom duration at diagnosis
(4.5 years) and frequent prescription of inappropriate medications reflect inadequate knowledge of RA among primary healthcare providers in Senegal. Long times to diagnosis have also
been reported in Nigeria [6] and in Quebec [12]. The high disease
activity in our patients, with a mean DAS28 of 6.5 1.3, is
probably ascribable to the diagnostic delay and inappropriate
treatment. An important finding from our study is that the contrast between the high level of disease activity and the relatively
low disease severity, with only one-third of the patients having
joint erosions and few patients having extra-articular manifestations. The low disease severity suggests that, with appropriate
early treatment, RA in Senegal may be less severe than in other
ethnic groups. It should be borne in mind, however, that a study
from the USA comparing RA in African–Americans and
Caucasians who had access to similar management resources
found no evidence of clinical or radiological differences between
the two groups [13].
The preponderance of females in our population is consistent
with the usual ratio of nine females to one male in younger
populations; the proportion of males is higher among older
patients. Mean age in our patients was 40.3 years, in keeping
with earlier studies from sub-Saharan Africa [14–16]. Older
mean ages were reported in The Netherlands (55 years) [17] and
among African–Americans (54.7 years) [3].
One-fourth of our patients reported a family history of inflammatory joint disease, supporting a major role for genetic factors.
However, we had no data on the diagnoses in family members.
The only study of RA genetics conducted in Senegal suggested
a key role for HLA-DR3 and HLA-DR10 [18]. The presence
of sickle cell disease or trait in some of our patients may be
ascribable to chance, given the high prevalence of haemoglobin
S alleles in sub-Saharan Africa. A study done in Togo found no
effect of haemoglobin S on the expression of inflammatory
joint disease [19].
Extra-articular manifestations of RA were uncommon in
studies of black African patients [5, 14, 20], whose open design
and small size, however, indicate a need for caution when interpreting the results. Among black Colombians with RA, 38% had
extra-articular manifestations [3]. In our study, in addition to
inflammatory anaemia (48% of the patients), 13% of the patients
had sicca syndrome with xerophthalmia and xerostomia. Anaemia
was the most common extra-articular manifestation (40% at
diagnosis) in a study of black patients in South Africa [14].
Rheumatoid nodules, a sign of severe RA, were found in only
FIG. 1. Photographs and anteroposterior radiographs of the hands of a patient with RA symptoms of 8 years of duration. Note the scars on the dorsal aspect of the wrists
suggesting previous traditional scarification treatment for synovitis.
Presentation and severity of RA in Senegal
3% of our patients, despite the high prevalence (78%) of the RFs.
Among black Africans in Kenya, 31.5% had rheumatoid nodules
at the diagnosis of RA [16]. Nodules caused by bacterial, fungal or
parasitic infections may mimic rheumatoid nodules [6]. Other
extra-articular manifestations were rare in our population. The
severity of the disease was consistent with the high prevalence of
RFs and anti-CCP antibodies, which are associated with greater
disease severity [21]. The high VAS pain score and laboratory
evidence of inflammation, two predictors of radiographical
destruction [22], were consistent with the presence of structural
damage in 56% of our patients, the mean modified Sharp score
being 21.8 47.7. Although earlier studies used different radiographical criteria [6, 14–16], their results are roughly similar to
ours, with mild to moderate overall joint destruction.
Our study has a number of limitations. The long time to
diagnosis may have biased our evaluation of disease severity at
the diagnosis of RA. Furthermore, many of our patients were
taking medications at the time of RA diagnosis. Treatment with
NSAIDs (47%) and glucocorticoids (19%) may have increased the
time to diagnosis and affected disease severity at diagnosis.
However, all patients were naive to DMARDs. The use of
benzathine benzylpenicillin in 18% of the patients indicates that
RA is often mistaken for rheumatic fever, which is endemic in
Senegal.
Conclusion
RA in Senegal is highly active at diagnosis, probably because
the diagnosis is made late. Thus, most of our patients had
involvement of numerous joints and strongly positive immunological tests. In contrast, systemic manifestations other than sicca
syndrome were uncommon. Studies of disease severity in
Senegalese patients treated early will be of interest. A useful
point of comparison will be the CLEAR registry of African–
American patients with early RA in the southeast USA [23].
One-fourth of the patients in our study had a family history of
inflammatory joint disease, supporting a strong pathogenical
role for genetic factors. Efforts are needed to increase awareness
of RA among primary healthcare providers in Senegal in order
to diminish mistaken diagnoses of rheumatic fever and to decrease
the time to the diagnosis of RA.
Rheumatology key messages
The diagnosis of RA is made late in Senegal, after 4 years on
average.
Only 56% of the patients have erosions at diagnosis, suggesting
limited aggressiveness of the disease.
Studies comparing disease severity after early treatment in
Senegal and other geographical areas are needed.
1113
Disclosure statement: The authors have declared no conflicts of
interest.
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