This cross-sectional study was conducted at Government Villupuram Medical College and Hospital. The sample size used was 21 based on a similar study [9]. Moreover, the presence of “Hy” band in serum of Rheumatoid arthritis was not a highlighted feature in the our parent article. The presence of “Hy” band was confirmed only in the synovial fluid in their study. So in order to confirm the presence of the band in serum, authors did a pilot study [8]. As a step further, authors did GAT for the same patients and tried to find its relation with “Hy” band. Hence, the study included 20 patients with active RA who were diagnosed according to the American College of Rheumatology/European League Against Rheumatism (EULAR) 2010 criteria [15]. The EULAR score was calculated at the first visit and monitored during subsequent follow-ups and those having a score below 6 are considered to be in the inactive stage of disease. The EULAR criteria is a comprehensive criteria which takes into account the number of joints involved, presence of RA factor, presence of Anti-CCP and duration of symptoms. It was developed for the purpose of selecting homogeneous populations for studies [16]. Patients having diabetes mellitus, metabolic diseases, diseases affecting neuromuscular function, renal diseases, hepatic diseases and other autoimmune diseases were excluded from the study.

Institutional ethical clearance for the study was obtained and the study was conducted for a period of two months from June 2018 to August 2018.

All relevant data such as duration of disease, presence of morning stiffness and treatment history were collected. The numbers of tender and swollen joints were counted and the patients were examined for the presence of hand deformities. Duruoz Hand Index (DHI) is a questionnaire evaluating quality of hand function in ADL such as eating, dressing, personal hygiene, etc., [17]. It is suggestive of the overall well being of the patient [4,5] and hence used as a measure of General Health in calculating DAS28. The questionnaire was filled by interview method.

Disease activity was measured by Disease Activity Score 28 [18]:

TJC 28=Tender joint count 28; SJC 28=Swollen joint count 28. The 28 joints are: Shoulder joint (2), Elbow joint (2), Knee joint (2), Wrist joint (2) and Hand’s PIP and MCP joints (20). ESR was measured by Westergren method in the Physiology laboratory. DAS28 is a well known and reliable measure of the severity of Rheumatoid arthritis [18]. The patients were split into three categories based on DAS28 scores as mild (DAS<5), moderate (DAS 5 to7) and severe (DAS>7). After taking consent and following all aseptic precautions, 3 cc blood was collected from each patient and the blood was stored at 4°C for three hours. The serum protein electrophoresis was carried out by automated capillary zone electrophoresis.

GAT was performed using Handgrip Dynamometer. The tests were conducted after 10 am in order to eliminate the influence of morning stiffness. Hand dominance was enquired. Before starting the test, the patient was asked to hold the apparatus and if the patient was unable to hold the apparatus, the GAT scores are taken as zero. If the patient was capable of holding the apparatus, the test was carried out with patient in sitting position, elbow flexed and forearm supinated and the patient was asked to clench the handle of the apparatus. The values are noted in kilograms. Three trials were conducted for each hand and the mean value was noted.

All the readings were tabulated and statistical analysis for correlation between GAT score and disease activity was performed by ANOVA. Student t-test was used for finding correlation between GAT scores and the presence of “Hy” band using epi info software version 7.2.2.

The study included 20 subjects with a male female ratio of 3:17. There was one patient with Juvenile Rheumatoid arthritis (JRA). On classifying patients based on DAS28 scores, three patients were in mild group, nine patients in moderate group and eight patients in severe group. The mean grip strength observed in dominant hand was 6.94±8.59 and in the non-dominant hand was 6.11±9.03 [Table/Fig-1]. On analysing the data using ANOVA test, there was a statistically significant correlation between disease activity and GAT with a p-value of 0.001 in both dominant and non-dominant hand [Table/Fig-2a,b,3 and 4]. As stated earlier, “Hy” band was positive in 70% of cases (n=14) [Table/Fig-5,6]. The presence of “Hy” band showed no correlation with GAT scores with p-value of 0.7279 in Dominant hand and p-value of 0.3337 in non-dominant hand [Table/Fig-7,8]. Deformities were present in eight cases-Boutainnaire (n=8), Swan neck (n=1), Ulnar deviation (n=5), Rheumatic nodules (n=1). The presence of deformities showed no correlation with GAT scores in both dominant and non-dominant hand [Table/Fig-9,10].

[Table/Fig-3]:

Graph representing the relationship between GAT scores of Dominant hand and DAS28 scores. Note the fall in Handgrip strength/Grip Ability in severe group.

[Table/Fig-4]:

Graph representing the relation between GAT scores of Non dominant hand and DAS28 scores. Note the fall in Handgrip strength/Grip Ability in severe group.

[Table/Fig-5]:

a) Figure showing the presence of “Hy” band in the prealbumin region; b) Magnified version.

[Table/Fig-6]:

The chart shows the number of people having “Hy” band in each group (Grouped according to Das28 scores).

Two sample ‘t’ test with equal variances (DOM GAT, by “Hy” band)

The relation between grip strength and general disability was established by previous studies [4,5]. GAT value of the dominant hand was found to have a significant positive correlation with handgrip [19]. This confirms the validity of GAT as a measure of handgrip strength. In the present study, authors compared GAT scores with disease activity. The present study revealed significant correlation with GAT and disease activity in both dominant and non-dominant hand. This is in line with a previous study [2] which found significant negative correlation with GAT and disease activity i.e., as Disease activity increases, GAT decreases.

Functional capacity of the patient decreases most rapidly at the early stages of the disease. The functional status and initiation of therapy in their first year of RA is predictive of long-term outcome [20]. In addition, the hand grip function is a sensitive measure of therapeutic response [21]. Hence GAT will serve as a quick and trustworthy tool for predicting prognosis and optimising therapy [Table/Fig-11].

[Table/Fig-11]:

Photograph demonstrating the GAT.

The study included patients on regular medication and patients not under regular medication. The treatment compliance was enquired by history and those who were on regular follow-up (one visit per month for the past two years) were considered to be on regular medication. Most patients were on Methotrexate (n=15) and severe cases were on steroids (n=8). On observation, the patients who were said to be on regular medication were able to perform the GAT test more efficiently. Since most patients did not have proper treatment records, treatment status was not subjected to statistical analysis.

In the present study, the prime focus was to find out the relation between GAT scores (loss of hand function) and the presence of “Hy” band. RA being an autoimmune disorder is known for remissions and exacerbations. A previous study by present authors [8] was a cross-sectional study and investigated the cases only for a short period of time, authors could not asses the inflammatory features present before the time of investigation accurately and the DAS28 score is a subjective measure, calculated only from the patient’s history. Hence there might be a memory recall bias. In order to reduce this bias, GAT scores can be used as a measure of disease activity. Thus, authors analysed the correlation between GAT scores and presence of “Hy” band. The present data revealed that there is no statistically significant relation between presence of “Hy” band and GAT scores.

Further studies are required to reveal the exact chemical nature of “Hy” band and confirm its relation with Amyloidosis in case of Rheumatoid arthritis patients. The factors influencing the presence of “Hy” band in RA patients needs to be evaluated. The therapeutic effect of increasing the retinol and retinol binding protein levels in preventing Amyloidosis in Rheumatoid arthritis patients, must be evaluated in a longitudinal study.

Our study concludes that the loss of hand function measured by GAT has positive correlation with disease activity. “Hy” band the surrogate marker of Amyloidosis shows no association with GAT. The treatment status of the patient is a possible confounding factor in the study. Way ahead, studies investigating the factors influencing the presence of “Hy” band are needed.