Chronic Cough Due to Tuberculosis and Other Infections

Prevalence of chronic cough, its risk factors and population attributable risk in the Burden of Obstructive Lung Disease (BOLD) study: a multinational cross-sectional study

Background

Chronic cough is a common respiratory symptom with an impact on daily activities and quality of life. Global prevalence data are scarce and derive mainly from European and Asian countries and studies with outcomes other than chronic cough. In this study, we aimed to estimate the prevalence of chronic cough across a large number of study sites as well as to identify its main risk factors using a standardised protocol and definition.

Methods

We analysed cross-sectional data from 33,983 adults (≥40 years), recruited between Jan 2, 2003 and Dec 26, 2016, in 41 sites (34 countries) from the Burden of Obstructive Lung Disease (BOLD) study. We estimated the prevalence of chronic cough for each site accounting for sampling design. To identify risk factors, we conducted multivariable logistic regression analysis within each site and then pooled estimates using random-effects meta-analysis. We also calculated the population attributable risk (PAR) associated with each of the identifed risk factors.

Findings

The prevalence of chronic cough varied from 3% in India (rural Pune) to 24% in the United States of America (Lexington,KY). Chronic cough was more common among females, both current and passive smokers, those working in a dusty job, those with a history of tuberculosis, those who were obese, those with a low level of education and those with hypertension or airflow limitation. The most influential risk factors were current smoking and working in a dusty job.

Interpretation

Our findings suggested that the prevalence of chronic cough varies widely across sites in different world regions. Cigarette smoking and exposure to dust in the workplace are its major risk factors.

Funding

Wellcome Trust.

Clinical characteristics of patients with chronic cough in Guangdong, China: a multicenter descriptive study

Background

The clinical characteristics of patients with chronic cough are reported only in single-center survey in China, being significantly different from that in western countries. Here, we performed a multicenter study to describe the clinical characteristics of chronic cough patients.

Methods

A cross-sectional observational survey was conducted in thirteen tertiary hospitals of Guangdong, South China. Relevant data were recorded using a standardized questionnaire and analyzed, including demographics, educational attainment, cough features, and concomitant symptoms.

Results

Of 933 patients in this study, the median age was 40.0 (IQR 31.0–52.0) years with a peaked age of 30–39 years. The proportion of females (487, 52.2 %) was comparable to that of males (446, 47.8 %). Up to 81.9 % of the patients were non-smokers. More than two-thirds of the subjects with chronic cough had a low educational level. The median cough duration was 6.0 (IQR 3.0–24.0) months, and 73.0 % of chronic cough patients presented with dry cough. Laryngeal paresthesia was the most common concomitant symptom (704, 75.5 %), followed by rhinitis/sinusitis-related (350, 37.5 %) and respiratory symptoms (322, 34.5 %). Rhinitis/sinusitis-related symptoms more frequently occurred in patients with productive cough than in those with dry cough (49.0 % vs. 33.0 %, P < 0.001). Moreover, female patients displayed an older age and a higher prevalence of nocturnal cough compared to male patients (both P < 0.05).

Conclusions

Our results show an equal gender, young profile and laryngeal paresthesia in patients with chronic cough, and different clinical features between females and males.

Sensitivity and specificity of tuberculosis signs and symptoms screening and adjunct role of social pathology characteristics in predicting bacteriologically confirmed tuberculosis in Myanmar

BACKGROUND

Globally, using tuberculosis signs and symptoms (TB-SS) as a screening tool has become less important due to its low sensitivity and specificity. We analyzed data from the Myanmar National Tuberculosis (TB) prevalence survey in 2010. The various TB screening models were developed to predict TB by using logistic regression analysis, and their performance on TB prediction was compared by the measures of overall performance, calibration and discrimination ability, and sensitivity and specificity to determine whether social pathology characteristics could be used as a TB screening tool.

RESULTS

Among 51,367 participants, 311 (0.6%) had bacteriologically confirmed TB, of which 37.2% were asymptomatic and 2% had a normal chest X-ray. Out of 32 various combinations of signs and symptoms, having any signs and symptoms gave the best sensitivity of 59.8% and specificity of 67.2%, but chest X-ray (CXR) alone gave the highest sensitivity (95.1%) and specificity (86.3%). The next best combination was cough only with a sensitivity of 24.4% and specificity of 85%. Other combinations had poor sensitivity (< 10%). Among various TB screening models, the overall performance R2 was higher in the combined models of social pathology and TB signs and symptoms as well as the social pathology model, compared to TB-SS models (> 10% versus < 3%), although all TB screening models were perfect to predict TB (Brier score = 0). The social pathology model shows a better calibration, more closer to 45° line of calibration plot with Hosmer-Lemeshow test p value = 0.787, than the combined models while it had a better discrimination ability in area under the curve, AUC = 80.4%, compared to TB-SS models with any signs and symptoms, AUC = 63.5% and with any cough, AUC = 57.1% (DeLong p value = 0.0001). Moreover, at the propensity score cutoff value ≥ 0.0053, the combined and social pathology models had sensitivity of ~ 80% and specificity of ~ 70%. The highest population attributable fraction to predict TB by social pathology characteristics was male gender (42.6%), age ≥ 55 years (31.0%), and underweight (30.4%).

CONCLUSION

Over one-third of bacteriologically confirmed TB was asymptomatic. The conventional TB-SS screening tool using any TB signs and symptoms had a lower sensitivity and specificity compared to CXR and social pathology screening tools. The social pathology characteristics as TB screening tool had good calibration and can improve the discrimination ability to predict TB than TB-SS screenings and should be encouraged.

Assessment of knowledge, attitude and practice on tuberculosis among teacher trainees of Samtse College of Education, Bhutan

Background

Tuberculosis (TB) is a major public health problem in Bhutan despite the implementation of directly observed treatment short-course since 1997. This study aimed to assess the knowledge, attitude and practice on TB among the teacher trainees of Samtse College of Education.

Methodology

A cross-sectional study was conducted among the teacher trainees of Samtse College of Education. A standardized pretested questionnaire was distributed and self-administered. The participants were selected randomly using randomization. The data was entered in Epi-data 4.4.2.1 and analysed using STATA version 13. A score of 1 point for a correct answer and 0 for wrong/don’t know answer was given. The knowledge, attitude and practice score were divided into good and poor based on 50% cut off. Logistic regression was used for the analysis to identify the significant covariates.

Results

A total of 420 trainees responded to the survey questionnaire. The average knowledge score on TB was 10.7 (Range = 0–21). Two hundred and forty respondents (58.6%) had low knowledge (mean score 7.8±2.5) on TB. Cough, chest pain and weight loss were correctly reported as the symptoms of TB by 306 (72.9%), 187(44.5%) and 187 (44.5%) participants. Eighty-nine-point five percent (376) of participants reported coughing as the main route of TB transmission and 85% (357) of the participants said that it could be prevented by covering the mouth while coughing. In multivariable analysis; the trainees in the junior years of college had good knowledge of TB compared with the senior years (adjusted odds ratio [AOR] 2.02; 95% confidence interval [CI] 1.18–3.5; p-value 0.011). Respondents previously treated for TB were more likely to have good knowledge on TB compared to those who never had TB in the past (AOR 2.39; 95% CI 1.07–5.31; p-value 0.033). The majority (93%) of respondents had a good attitude towards TB cases. Female trainees were 2.4 (95% CI 1.02–5.62; p-value 0.045) times more likely than male trainees to have a positive attitude towards TB. Eighty-eight percent of the respondents reported that they would visit the hospital if they had TB symptoms. The mean score for the practice on TB was 1.33±0.59 (Range:0–2).

Conclusion

In this study, the majority of the trainees had poor knowledge on TB, especially among the trainees in senior years of college and those who had never suffered from TB. The attitude towards TB was good especially among the female trainees. However, the overall practice was poor among the participants. Therefore, the Ministry of Health should collaborate with relevant stakeholders especially the Ministry of Education to incorporate topics on TB in the syllabus of students and colleges to create awareness on it.

Chronic cough in adults

Cough, a defense mechanism for clearing the airways of secretions, exudate, or foreign bodies, may become a troublesome symptom. Chronic cough, one of the most frequent symptoms requiring medical attention, is often not due to identifiable causes in adults. Chronic productive cough defines chronic bronchitis, and thus is present in 100% of these patients, and frequently in patients with bronchiectasis, cystic fibrosis, and chronic infectious respiratory diseases. However, chronic cough is most frequently dry. Thus, chronic cough in adults is a difficult syndrome requiring multidisciplinary approaches, particularly to diagnose and treat the most frequent identifiable causes, but also to decide which patients may benefit by treating the central cough hypersensitivity by neuromodulatory therapy and/or non-pharmacologic treatment (speech pathology therapy). Recent guidelines provide algorithms for diagnosis and assessment of cough severity; particularly chronic cough in adults. After excluding life-threatening diseases, chronic cough due to identifiable causes (triggers and/or diseases), particularly smoking and/or the most frequent diseases (asthma, chronic bronchitis, chronic obstructive pulmonary disease, eosinophilic bronchitis, and adverse reactions to drugs [angiotensin-converting enzyme inhibitors and sitagliptin]) should be treated by avoiding triggers and/or according to guidelines for each underlying disease. In patients with troublesome chronic cough due to unknown causes or persisting even after adequate avoidance of triggers, and/or treatment of the underlying disease(s), a symptomatic approach with neuromodulators and/or speech pathology therapy should be considered. Additional novel promising neuromodulatory agents in clinical development (e.g., P2X3 inhibitors) will hopefully become available in the near future.

Asymptomatic Human Paragonimiasis among the Karen People in Tak Province, Thailand: A Case Report

During the mobile clinic activities in Tak Province, Thailand, Paragonimus sp. eggs were found in a fecal sample of a 72-year-old Karen resident. Paragonimus DNA was amplified from the stool sample and identified to P. heterotremus. The patient did not have any symptoms. Apparent pulmonary lesion was not found on the chest X-ray. The patient admitted habitual consumption of semi-cooked or roasted waterfall crabs for several years. The waterfall crabs collected from stream near the village were found negative for Paragonimus metacercariae. In northern Thailand, paragonimiasis remains as one of the public health concerns and should be ruled out for asymptomatic pulmonary patients.

The burden of non-TB lung disease presenting to TB clinics in The Gambia: preliminary data in the Xpert® MTB/Rif era

In some low and middle-income countries, 10-20% of patients presenting with a persistent cough have tuberculosis (TB). Once TB is excluded, health service provision for alternative diagnoses is limited. We prospectively studied patients with two Xpert-negative sputum results presenting to a TB clinic in The Gambia. Of 239 patients, 108 did not have TB; 65/102 (6 were lost to follow-up) had alternative diagnoses, 24.6% of which were non-respiratory; 37/102 had no diagnosis, 27.0% of whom were HIV-1-positive; 37.8% had a history of TB and 24.3% smoked. We highlight the need for general health service integration with TB platforms and exploration of non-TB patients with chronic respiratory symptoms.

Cough Due to TB and Other Chronic Infections: CHEST Guideline and Expert Panel Report

BACKGROUND

Cough is common in pulmonary TB and other chronic respiratory infections. Identifying features that predict whether pulmonary TB is the cause would help target appropriate individuals for rapid and cost-effective screening, potentially limiting disease progression and preventing transmission to others.

METHODS

A systematic literature search for individual studies to answer eight key questions (KQs) was conducted according to established Chest Organization methods by using the following databases: MEDLINE via PubMed, Embase, Scopus, and the Cochrane Database of Systematic Reviews from January 1, 1984, to April 2014. Searches for KQ 1 and KQ 3 were updated in February 2016. An updated KQ 2 search was undertaken in March 2017.

RESULTS

Even where TB prevalence is greatest, most individuals with cough do not have pulmonary TB. There was no evidence that 1, 3, or 4 weeks' duration were better predictors than cough lasting ≥ 2 weeks to screen for pulmonary TB. In people living with HIV (PLWHIV), screening for fever, night sweats, hemoptysis, and/or weight loss in addition to cough (any World Health Organization [WHO]-endorsed symptom) increases the diagnostic sensitivity for TB. Although the diagnostic accuracy of symptom-based screening remains low, the negative predictive value of the WHO-endorsed symptom screen in PLWHIV may help to risk-stratify individuals who are not close TB contacts and who do not require further testing for pulmonary TB in resource-limited settings. However, pregnant PLWHIV are more likely to be asymptomatic, and the WHO-endorsed symptom screen is not sensitive enough to be reliable. Combined with passive case finding (PCF), active case finding (ACF) identifies pulmonary TB cases earlier and possibly when less advanced. Whether outcomes are improved or transmission is reduced is unclear. Screening asymptomatic patients is cost-effective only in populations with a very high TB prevalence. The Xpert MTB/RIF assay on sputum is more cost-effective than clinical diagnosis. To our knowledge, no published comparative studies addressed whether the rate of cough resolution is a reliable determinant of the response to treatment or whether the rate of cough resolution was faster in the absence of cavitary lung disease. All studies on cough prevalence in Mycobacterium avium complex (MAC) lung disease, other nontuberculous mycobacterial infections, fungal lung disease, and paragonimiasis were of poor quality and were excluded from the evidence review.

CONCLUSIONS

On the basis of relatively few studies of fair to good quality, we conclude that most individuals at high risk and household contacts with cough ≥ 2 weeks do not have pulmonary TB, but we suggest screening them regardless of cough duration. In PLWHIV, the addition of the other WHO-endorsed symptoms increases the diagnostic sensitivity of cough. Earlier screening of patients with cough will help diagnose pulmonary TB sooner but will increase the cost of screening. The addition of ACF to PCF will increase the number of pulmonary TB cases identified. Screening asymptomatic individuals is cost-effective only in groups with a very high TB prevalence. Data are insufficient to determine whether cough resolution is delayed in individuals with cavitary lung disease or in those for whom treatment fails because of drug resistance, poor adherence, and/or drug malabsorption compared with results in other individuals with pulmonary TB. Cough is common in patients with lung infections due to MAC, other nontuberculous mycobacteria, fungal diseases, and paragonimiasis.

Risk of self-reported symptoms or diagnosis of active tuberculosis in relationship to low body mass index, diabetes and their co-occurrence

OBJECTIVE

Globally, tuberculosis prevalence has declined, but its risk factors have varied across place and time - low body mass index (BMI) has persisted while diabetes has increased. Using India's National Family Health Survey (NFHS), wave 3 and World Health Survey (WHS) data, we examined their relationships to support projection of future trends and targeted control efforts.

METHODS

Multivariate logistic regressions at the individual level with and without diabetes/BMI interactions assessed the relationship between tuberculosis, diabetes and low BMI and the importance of risk factor co-occurrence. Population-level analyses examined how tuberculosis incidence and prevalence varied with diabetes/low BMI co-occurrence.

RESULTS

In NFHS, diabetic individuals had higher predicted tuberculosis risks (diabetic vs. non-diabetic: 2.50% vs. 0.63% at low BMI; 0.81% vs. 0.20% at normal BMI; 0.37% vs. 0.09% at high BMI), which were not significantly different when modelled independently or allowing for risk modification with diabetes/low BMI co-occurrence. WHS findings were generally consistent. Population-level analysis found that diabetes/low BMI co-occurrence may be associated with elevated tuberculosis risk, although its predicted effect on tuberculosis incidence/prevalence was generally ≤0.2 percentage points and not robustly statistically significant.

CONCLUSIONS

Concerns about the additional elevation of tuberculosis risk from diabetes/low BMI co-occurrence and hence the need to coordinate tuberculosis control efforts around the nexus of co-occurring diabetes and low BMI may be premature. However, study findings robustly support the importance of individually targeting low BMI and diabetes as part of ongoing tuberculosis control efforts.

Tuberculin skin test positivity without tuberculosis contact: A major challenge in childhood

AIM

Worldwide, tuberculin skin tests (TSTs) commonly give false positive results for those who had been given the Bacillus-Calmette-Guerin vaccine such as is routinely administered in Turkey. This study aimed to evaluate the patients referred to us who had positive TSTs despite lack of tuberculosis (TB) disease contacts.

METHODS

Between September 2011 and September 2012, 183 patients were prospectively evaluated for differential diagnosis of TST positivity despite lack of TB disease contact. They were then followed up by us to determine an accurate diagnosis.

RESULTS

Among our patients' most common symptoms indicating a need for TST were chronic cough, productive cough or sputum expectoration, and recurrent or persistent wheezing. Chest x-rays were taken of all patients, and the findings were noted. Interferon gamma release assays were performed on 75% of the patients, of which 96% were negative for TB. The most common final diagnoses were asthma (44%), allergic rhinitis (13%), bronchopneumonia (11%) and reactive lymphadenitis (6.5%). Further evaluations for TB were required of 36 patients, and TB disease was established in 12 of them (6.5%).

CONCLUSIONS

In patients who had had no known TB contact, the most common symptom indicating need for TST was chronic cough; the most common diagnoses were asthma and allergic rhinitis. Cavitary lesions, haemoptysis, persistent infiltration, pleural effusion and thoracic lymphadenopathy despite antibiotherapy should alert physicians to the possibility of TB.

Tobacco smoking, alcohol drinking, diabetes, low body mass index and the risk of self-reported symptoms of active tuberculosis: individual participant data (IPD) meta-analyses of 72,684 individuals in 14 high tuberculosis burden countries

BACKGROUND

The effects of multiple exposures on active tuberculosis (TB) are largely undetermined. We sought to establish a dose-response relationship for smoking, drinking, and body mass index (BMI) and to investigate the independent and joint effects of these and diabetes on the risk of self-reported symptoms of active TB disease.

METHODS AND FINDINGS

We analyzed 14 national studies in 14 high TB-burden countries using self-reports of blood in cough/phlegm and cough lasting > = 3 weeks in the last year as the measures of symptoms of active TB. The random effect estimates of the relative risks (RR) between active TB and smoking, drinking, diabetes, and BMI<18.5 kg/m2 were reported for each gender. Floating absolute risks were used to examine dyads of exposure. Adjusted for age and education, the risks of active TB were significantly associated with diabetes and BMI<18.5 kg/m2 in both sexes, with ever drinking in men and with ever smoking in women. Stronger dose-response relationships were seen in women than in men for smoking amount, smoking duration and drinking amount but BMI<18.5 kg/m2 showed a stronger dose-response relationship in men. In men, the risks from joint exposures were statistically significant for diabetics with BMI<18.5 kg/m2 (RR = 6.4), diabetics who smoked (RR = 3.8), and diabetics who drank alcohol (RR = 3.2). The risks from joint risk factors were generally larger in women than in men, with statistically significant risks for diabetics with BMI<18.5 kg/m2 (RR = 10.0), diabetics who smoked (RR = 5.4) and women with BMI<18.5 kg/m2 who smoked (RR = 5.0). These risk factors account for 61% of male and 34% of female estimated TB incidents in these 14 countries.

CONCLUSIONS

Tobacco, alcohol, diabetes, and low BMI are significant individual risk factors but in combination are associated with triple or quadruple the risk of development of recent active TB. These risk factors might help to explain the wide variation in TB across countries.

Factors associated with pulmonary tuberculosis among patients seeking medical attention at referral clinics for tuberculosis

OBJECTIVE

The identification of behavioral and clinical factors that are associated with pulmonary tuberculosis might improve the detection and treatment of the disease, thereby reducing its duration and transmission. Our objective was to identify sociodemographic, clinical, and behavioral factors that are associated with the diagnosis of pulmonary tuberculosis.

METHODS

This was a cross-sectional study conducted between April of 2008 and March of 2009 at three health care clinics in the city of Fortaleza, Brazil. We selected 233 patients older than 14 years of age who spontaneously sought medical attention and presented with cough for > 2 weeks. Sociodemographic, clinical, and behavioral data were collected. Sputum smear microscopy for AFB and mycobacterial culture were also carried out, as were tuberculin skin tests and chest X-rays. The patients were divided into two groups (with and without pulmonary tuberculosis). The categorical variables were compared by the chi-square test, followed by logistic regression analysis when the variables were considered significant.

RESULTS

The prevalence of pulmonary tuberculosis was 41.2%. The unadjusted OR showed that the following variables were statistically significant risk factors for pulmonary tuberculosis: fever (OR = 2.39; 95% CI, 1.34-4.30), anorexia (OR = 3.69; 95% CI, 2.03-6.75), and weight loss (OR = 3.37; 95% CI, 1.76-6.62). In the multivariate analysis, only weight loss (OR = 3.31; 95% CI, 1.78-6.14) was significantly associated with pulmonary tuberculosis.

CONCLUSIONS

In areas with a high prevalence of tuberculosis, weight loss could be used as an indicator of pulmonary tuberculosis in patients with chronic cough for > 2 weeks.

Diabetes mellitus and tuberculosis in countries with high tuberculosis burdens: individual risks and social determinants

BACKGROUND

A growing body of evidence supports the role of type 2 diabetes as an individual-level risk factor for tuberculosis (TB), though evidence from developing countries with the highest TB burdens is lacking. In developing countries, TB is most common among the poor, in whom diabetes may be less common. We assessed the relationship between individual-level risk, social determinants and population health in these settings.

METHODS

We performed individual-level analyses using the World Health Survey (n = 124,607; 46 countries). We estimated the relationship between TB and diabetes, adjusting for gender, age, body mass index, education, housing quality, crowding and health insurance. We also performed a longitudinal country-level analysis using data on per-capita gross domestic product and TB prevalence and incidence and diabetes prevalence for 1990-95 and 2003-04 (163 countries) to estimate the relationship between increasing diabetes prevalence and TB, identifying countries at risk for disease interactions.

RESULTS

In lower income countries, individuals with diabetes are more likely than non-diabetics to have TB [univariable odds ratio (OR): 2.39; 95% confidence interval (CI): 1.84-3.10; multivariable OR: 1.81; 95% CI: 1.37-2.39]. Increases in TB prevalence and incidence over time were more likely to occur when diabetes prevalence also increased (OR: 4.7; 95% CI: 1.0-22.5; OR: 8.6; 95% CI: 1.9-40.4). Large populations, prevalent TB and projected increases in diabetes make countries like India, Peru and the Russia Federation areas of particular concern.

CONCLUSIONS

Given the association between diabetes and TB and projected increases in diabetes worldwide, multi-disease health policies should be considered.

Cough: a worldwide problem

Cough is a common and important respiratory symptom that can produce significant complications for patients and be a diagnostic challenge for physicians. An organized approach to evaluating cough begins with classifying it as acute, subacute, or chronic in duration. Acute cough lasting less than 3 weeks may indicate an acute underlying cardiorespiratory disorder but is most commonly caused by a self-limited viral upper respiratory tract infection (eg, common cold). Subacute cough lasting 3 to 8 weeks commonly has a postinfectious origin; among the causes, Bordetella pertussis infection should be included in the differential diagnosis. Chronic cough lasts longer than 8 weeks. When a patient is a nonsmoker, is not taking an angiotensin-converting enzyme inhibitor, and has a normal or near-normal chest radiograph, chronic cough is most commonly caused by upper airway cough syndrome, asthma, nonasthmatic eosinophilic bronchitis, or gastroesophageal reflux disease alone or in combination.