Tuberculosis (TB) is known as a disease that prone to spatial clustering. Recent development has seen a sharp rise in the number of epidemiologic studies employing Geographical Information System (GIS), particularly in identifying TB clusters and evidences of etiologic factors. The aim of this systematic review is to determine evidence of TB clustering, type of spatial analysis commonly used and the application of GIS in TB surveillance and control. A literature search of articles published in English language between 2000 and November 2015 was performed using MEDLINE and Science Direct using relevant search terms related to spatial analysis in studies of TB cluster. The search strategy was adapted and developed for each database using appropriate subject headings and keywords. The literature reviewed showed strong evidence of TB clustering occurred in high risk areas in both developed and developing countries. Spatial scan statistics were the most commonly used analysis and proved useful in TB surveillance through detection of outbreak, early warning and identifying area of increased TB transmission. Among others are targeted screening and assessment of TB program using GIS technology. However there were limitations on suitability of utilizing aggregated data such as national cencus that were pre-collected in explaining the present spatial distribution among population at risk. Spatial boundaries determined by zip code may be too large for metropolitan area or too small for country. Nevertheless, GIS is a powerful tool in aiding TB control and prevention in developing countries and should be used for real-time surveillance and decision making.
Objective: Although osteoarthritis (OA) is widely accepted as a degenerative disease, autoimmune processes are believed to be involved in the pathogenesis. There are limited studies in this area and most of them focused on antibodies against chondrocyte membrane. In an attempt to address the paucity of evidence in this regard, we explored the clinical significance of antinuclear antibody (ANA) in primary osteoarthritis of the knee (OAK).
Method: We studied 106 patients with primary osteoarthritis of at least 1 knee and 63 healthy controls from two tertiary centres in Malaysia from September 2005 to May 2012. All subjects were tested for ANA by immunofluorescence testing, and a titer of 1:40 and above was considered positive. Besides, the radiographs of bilateral knees were evaluated for grading, tibiofemoral compartment involvement and total knee replacement (TKR) implants. We compared the clinical characteristics between the ANA positive and ANA negative OAK cases.
Results: The incidence of ANA positivity among the cases (39.4 %) was higher than the controls (27 %) but this difference was statistically insignificant (p=0.754). ANA positive cases showed significantly higher incidence of bilateral and Grade IV OAK with higher frequency of TKR. In the multiple regression analysis, bilateral OAK (p< 0.0001; odds ratio 9.00), Grade IV OAK (p<0.001, odds ratio 3.44) and TKR (p=0.009; odds ratio 2.97) remained associated with ANA positivity.
Conclusions: ANA test is a potential prognostic tool in primary OAK and its positivity is associated with the clinical outcomes of bilateral, Grade IV OAK and TKR.
Study site: Universiti Kebangsaan Malaysia Medical Centre, Kuala Lumpur; Putrajaya Hospital, Wilayah Persekutuan