Search strategy
The present systematic review of cross-sectional studies was conducted based on the Preferred Reporting Items for Systematic reviews and Meta-analysis (PRISMA) Protocol (File1). A systematic literature search was conducted in Web of Science, MEDLINE/PubMed, Scopus, Google Scholar, Cochrane Library, and Science Direct databases. Studies published between January 2001 and March 2019 was collected. Medical subject headings (MeSH) and non-MeSH keywords were searched within titles, abstracts or keywords: Search strategy was as “pulmonary fungal”, “pulmonary coinfection”, OR “Pulmonary mycosis”, “pulmonary fungal infections/agents”, OR “Polymicrobial infection”, OR “Secondary infection”, OR “Mixed infections”, “pulmonary Candidiasis”, “fungi coinfection”, “Fungal co-colonization”, AND “pulmonary tuberculosis”, OR “pulmonary TB”. Only studies published in English were included. The literature search was conducted by A.K and A.S. Reference lists of recruited studies were checked to find additional relevant articles.
Inclusion and exclusion criteria
Titles, abstracts, and full texts of articles were read to find relevant studies and check eligibility criteria. Inclusion criteria were a) cross-sectional design; and b) assessing coinfection of candidiasis and pulmonary tuberculosis. Studies published before 2001, case reports, meeting reports, letters to editors, abstracts, case series, congress articles, editorials, literatures reporting inadequate data, articles published in languages other than English, duplicate publications, and narrative or meta-analysis/systematic reviews were excluded. Two reviewers (AK, AS) independently assessed the studies based on the inclusion and exclusion criteria. Disagreements on the inclusion or exclusion of studies were resolved by discussions between the two reviewers or by involving a third researcher.
Quality evaluation
Appraisal tool for Cross-Sectional Studies (AXIS) was used for assessing the quality of the included studies. Using this check, twenty items were evaluated in each study. If the related data was documented, a question was scored ‘yes’. In case of any doubt or indistinct data, a question was marked ‘no’ or ‘can’t tell’. According to the scoring system and the number of questions scored ‘yes’, the quality of studies was finally categorized as either ‘strong’, ‘intermediate’, or ‘weak’ [16]. Studies with weak quality were excluded (File 2).
Data extraction
The following data was extracted and tabulated: first author’s name, year of publication, location (country), sample size (TB+), rate of candida coinfection, and detection method.
Statistical analysis
We used Comprehensive Meta-Analysis software (Version 3.3.070) for meta-analysis. Statistical significance level was considered as P < 0.05. Random effects model was used to calculate overall effects. Sources of between-study heterogeneity were assessed using Cochran’s Q and I square (I2) tests and subgroup analysis. Egger’s regression asymmetry test was used to detect publication bias. The correlations between pulmonary candidiasis coinfection and patients’ characteristics such as age, gender, body mass index (BMI), and factors such as alcohol consumption, smoking, and diabetes mellitus (DM) were also scrutinized by Spearman correlation.