Obstructive sleep apnea and excessive daytime sleepiness among commercial motor vehicle drivers in Lusaka, Zambia

STUDY OBJECTIVES

Obstructive sleep apnea (OSA) is a risk factor for a major public health problem, car crashes, due to excessive daytime sleepiness (EDS). Commercial vehicle driving (CVD) is a hazardous occupation, having a high fatality rate worldwide. There have been no studies on EDS and OSA in Zambia despite the high rate of annual road traffic accidents (RTAs). We aim to determine the prevalence of EDS and OSA risk among CVDs in Lusaka, Zambia, to assess the impact of OSA on high RTA rates.

METHODS

This was a cross-sectional study. The STOP BANG questionnaire and the Epworth Sleepiness Scale were used. Consecutive sampling of drivers was done who were divided into low and high risk of OSA (HROSA). The risk factors associated with OSA in the bivariate analyses were subjected to a multivariate logistic regression model.

RESULTS

One hundred thirty-six drivers participated in the study (all male) with a mean age of 48 ± 5 years. The prevalence of HROSA was 22.8% out of whom 67.7% also had a EDS. Only 9.6% of the total cohort had EDS without HROSA. Using Fisher's exact test, HROSA was significantly associated with older age (> 50 years, P < .001), obesity (body mass index >30, P < .001), neck circumference of > 40 cm (P = .032), and hypertension (P < .001). Snoring and EDS were significantly associated with RTAs (P < .0001 and P = .007, respectively).

CONCLUSIONS

High risk of OSA and EDS are common among CMV drivers in Zambia and underdiagnosed. The risk factors for OSA are amenable to preventive interventions.

CITATION

Simpamba K, May JL, Waghat A, Attarian H, Mateyo K. Obstructive sleep apnea and excessive daytime sleepiness among commercial motor vehicle drivers in Lusaka, Zambia. J Clin Sleep Med. 2023;19(7):1191-1198.

A mixed methods study on men's and women's tuberculosis care journeys in Lusaka, Zambia-Implications for gender-tailored tuberculosis health promotion and case finding strategies

Men and women with undiagnosed tuberculosis (TB) in high burden countries may have differential factors influencing their healthcare seeking behaviors and access to TB services, which can result in delayed diagnoses and increase TB-related morbidity and mortality. A convergent, parallel, mixed-methods study design was used to explore and evaluate TB care engagement among adults (≥18 years) with newly diagnosed, microbiologically-confirmed TB attending three public health facilities in Lusaka, Zambia. Quantitative structured surveys characterized the TB care pathway (time to initial care-seeking, diagnosis, and treatment initiation) and collected information on factors influencing care engagement. Multinomial multivariable logistic regression was used to determine predicted probabilities of TB health-seeking behaviors and determinants of care engagement. Qualitative in-depth interviews (IDIs; n = 20) were conducted and analyzed using a hybrid approach to identify barriers and facilitators to TB care engagement by gender. Overall, 400 TB patients completed a structured survey, of which 275 (68.8%) and 125 (31.3%) were men and women, respectively. Men were more likely to be unmarried (39.3% and 27.2%), have a higher median daily income (50 and 30 Zambian Kwacha [ZMW]), alcohol use disorder (70.9% [AUDIT-C score ≥4] and 31.2% [AUDIT-C score ≥3]), and a history of smoking (63.3% and 8.8%), while women were more likely to be religious (96.8% and 70.8%) and living with HIV (70.4% and 36.0%). After adjusting for potential confounders, the probability of delayed health-seeking ≥4 weeks after symptom onset did not differ significantly by gender (44.0% and 36.2%, p = 0.14). While the top reasons for delayed healthcare-seeking were largely similar by gender, men were more likely to report initially perceiving their symptoms as not being serious (94.8% and 78.7%, p = 0.032), while women were more likely to report not knowing the symptoms of TB before their diagnosis (89.5% and 74.4%; p = 0.007) and having a prior bad healthcare experience (26.4% and 9.9%; p = 0.036). Notably, women had a higher probability of receiving TB diagnosis ≥2 weeks after initial healthcare seeking (56.5% and 41.0%, p = 0.007). While men and women reported similar acceptability of health-information sources, they emphasized different trusted messengers. Also, men had a higher adjusted probability of stating that no one influenced their health-related decision making (37.9% and 28.3%, p = 0.001). In IDIs, men recommended TB testing sites at convenient community locations, while women endorsed an incentivized, peer-based, case-finding approach. Sensitization and TB testing strategies at bars and churches were highlighted as promising approaches to reach men and women, respectively. This mixed-methods study found important differences between men and women with TB in Zambia. These differences suggest the need for gender-tailored TB health promotion, including addressing harmful alcohol use and smoking among men, and sensitizing HCWs to prolonged delays in TB diagnosis among women, and also using gender-specific approaches as part of community-based, active case-finding strategies to improve TB diagnosis in high burden settings.

The Performance of Computer-Aided Detection Digital Chest X-ray Reading Technologies for Triage of Active Tuberculosis Among Persons With a History of Previous Tuberculosis

BACKGROUND

Digital chest X-ray (dCXR) computer-aided detection (CAD) technology uses lung shape and texture analysis to determine the probability of tuberculosis (TB). However, many patients with previously treated TB have sequelae, which also distort lung shape and texture. We evaluated the diagnostic performance of 2 CAD systems for triage of active TB in patients with previously treated TB.

METHODS

We conducted a retrospective analysis of data from a cross-sectional active TB case finding study. Participants ≥15 years, with ≥1 current TB symptom and complete data on history of previous TB, dCXR, and TB microbiological reference (Xpert MTB/RIF) were included. dCXRs were evaluated using CAD4TB (v.7.0) and qXR (v.3.0). We determined the diagnostic accuracy of both systems, overall and stratified by history of TB, using a single threshold for each system that achieved 90% sensitivity and maximized specificity in the overall population.

RESULTS

Of 1884 participants, 452 (24.0%) had a history of previous TB. Prevalence of microbiologically confirmed TB among those with and without history of previous TB was 12.4% and 16.9%, respectively. Using CAD4TB, sensitivity and specificity were 89.3% (95% CI: 78.1-96.0%) and 24.0% (19.9-28.5%) and 90.5% (86.1-93.3%) and 60.3% (57.4-63.0%) among those with and without previous TB, respectively. Using qXR, sensitivity and specificity were 94.6% (95% CI: 85.1-98.9%) and 22.2% (18.2-26.6%) and 89.7% (85.1-93.2%) and 61.8% (58.9-64.5%) among those with and without previous TB, respectively.

CONCLUSIONS

The performance of CAD systems as a TB triage tool is decreased among persons previously treated for TB.

Patient Preferences for Strategies to Improve Tuberculosis Diagnostic Services in Zambia

IMPORTANCE

Delayed engagement in tuberculosis (TB) services is associated with ongoing transmission and poor clinical outcomes.

OBJECTIVE

To assess whether patients with TB have differential preferences for strategies to improve the public health reach of TB diagnostic services.

DESIGN, SETTING, AND PARTICIPANTS

A cross-sectional study was undertaken in which a discrete choice experiment (DCE) was administered between September 18, 2019, and January 17, 2020, to 401 adults (>18 years of age) with microbiologically confirmed TB in Lusaka, Zambia. The DCE had 7 attributes with 2 to 3 levels per attribute related to TB service enhancements. Latent class analysis was used to identify segments of participants with unique preferences. Multiscenario simulations were used to estimate shares of preferences for different TB service improvement strategies.

MAIN OUTCOMES AND MEASURES

The main outcomes were patient preference archetypes and estimated shares of preferences for different strategies to improve TB diagnostic services. Collected data were analyzed between January 3, 2022, to July 2, 2022.

RESULTS

Among 326 adults with TB (median [IQR] age, 34 [27-42] years; 217 [66.8%] male; 158 [48.8%] HIV positive), 3 groups with distinct preferences for TB service improvements were identified. Group 1 (192 participants [58.9%]) preferred a facility that offered same-day TB test results, shorter wait times, and financial incentives for testing. Group 2 (83 participants [25.4%]) preferred a facility that provided same-day TB results, had greater privacy, and was closer to home. Group 3 (51 participants [15.6%]) had no strong preferences for service improvements and had negative preferences for receiving telephone-based TB test results. Groups 1 and 2 were more likely to report at least a 4-week delay in seeking health care for their current TB episode compared with group 3 (29 [51.3%] in group 1, 95 [35.8%] in group 2, and 10 [19.6%] in group 3; P < .001). Strategies to improve TB diagnostic services most preferred by all participants were same-day TB test results alone (shares of preference, 69.9%) and combined with a small financial testing incentive (shares of preference, 79.3%), shortened wait times (shares of preference, 76.1%), or greater privacy (shares of preference, 75.0%). However, the most preferred service improvement strategies differed substantially by group.

CONCLUSIONS AND RELEVANCE

In this study, patients with TB had heterogenous preferences for TB diagnostic service improvements associated with differential health care-seeking behavior. Tailored strategies that incorporate features most valued by persons with undiagnosed TB, including same-day results, financial incentives, and greater privacy, may optimize reach by overcoming key barriers to timely TB care engagement.

Clinical and radiographic characteristics of presumptive tuberculosis patients previously treated for tuberculosis in Zambia

Background

Persistent respiratory symptoms and radiographic abnormalities are common among individuals previously treated for tuberculosis (TB) and may contribute to misdiagnosis and incorrect treatment when they seek care. We sought to determine if clinical and radiographic characteristics differed among previously treated, presumptive TB patients according to their current TB disease status.

Methods

Adults (>18 years of age) seeking care at a public health facility in Lusaka, Zambia were systematically evaluated for active TB using symptom screening and chest X-ray. All patients with presumptive TB submitted a sputum sample for microbiological TB testing. Patients who reported a prior history of TB treatment were included in the present analysis. ‘Confirmed TB’ was defined by the detection of TB using Xpert Ultra and/or liquid culture, while ‘possible TB’ was defined by the receipt of TB treatment without a positive Xpert Ultra or culture result. We evaluated the positive predictive value (PPV) of clinical symptoms and radiographic features for active TB alone and in combination.

Results

Of 740 presumptive TB patients, 144 (19%) had been previously treated for active TB. Of these, 19 (13%) patients had confirmed TB, 14 (10%) had possible TB, and 111 (77%) had no pulmonary TB. Overall, 119 (83%) patients had ≥1 current respiratory symptom—this did not differ according to current TB disease classification (95%, 93%, 79%; p = 0.23). Sixty-one patients (56%) had radiographic abnormalities suggestive of active TB and such findings were more common among patients with confirmed or possible TB compared to those without TB (93%, 71%, vs. 47%; p = 0.002). Most patients (n = 91, 83%) had at least one radiographic abnormality—no difference by current TB classification was observed (93%, 100%, 79%; p = 0.08). The PPV of any current respiratory symptom, active TB radiographic finding, or any radiographic abnormality for TB was 13% (95%CI: 7–21%), 21% (95%CI: 12–34) and 14% (95%CI: 9–23), respectively; combining clinical and radiographic characteristics did not significantly improve the PPV for active TB.

Conclusions

Among presumptive TB patients previously treated for TB, respiratory symptoms and radiographic abnormalities were common and poorly differentiated those with current active TB from those without current active TB. Reliance on clinical and radiographic characteristics alone in this patient population may result in substantial overtreatment and therefore, microbiological investigations should be used to inform TB treatment decisions whenever possible.

Congenital tracheobronchomegaly (Mounier-Kuhn syndrome) in a 28-year-old Zambian male: a case report

Congenital tracheobronchomegaly, also known as Mounier Kuhn Syndrome (MKS) is a rare respiratory disorder characterized by dilatation of the trachea and bronchi. We report a case of a 28-year-old male of African descent in Zambia, who presented with a history of chronic productive cough and repeated chest infections since childhood. He had been treated numerous times for lower respiratory tract infections, and had received empiric tuberculosis (TB) treatment based on chest radiograph findings, despite negative sputum microscopy and molecular tests for TB. Investigations revealed normal baseline blood results and sputum results. He however, had markedly increased levels of serum immunoglobulin E, and spirometry showed an obstructive pattern with significant post bronchodilator improvement. High-resolution computed tomography scan revealed tracheal dilatation, extensive bilateral bronchiectasis and tracheal and bronchial diverticula. The latter were also seen on bronchoscopy, confirming the diagnosis of Mounier-Kuhn syndrome. The patient was treated with combined inhaled corticosteroids and bronchodilators, as well as chest physiotherapy for mucus clearance, which led to improvement in his symptoms. Our case highlights how in low-resource settings, chronic lung diseases, particularly bronchiectasis, are often clinically and radiologically mistaken for and presumptively treated as TB (or its sequelae). Mounier-Kuhn syndrome, albeit rare, should be considered in the differential diagnosis of patients with recurrent lower respiratory tract infections or bronchiectasis. Multidisciplinary team meetings can help in the diagnosis of rare lung diseases.

Pathways to care and preferences for improving tuberculosis services among tuberculosis patients in Zambia: A discrete choice experiment

BACKGROUND

Delays in the diagnosis of tuberculosis (TB) contribute to a substantial proportion of TB-related mortality, especially among people living with HIV (PLHIV). We sought to characterize the diagnostic journey for HIV-positive and HIV-negative patients with a new TB diagnosis in Zambia, to understand drivers of delay, and characterize their preferences for service characteristics to inform improvements in TB services.

METHODS

We assessed consecutive adults with newly microbiologically-confirmed TB at two public health treatment facilities in Lusaka, Zambia. We administered a survey to document critical intervals in the TB care pathway (time to initial care-seeking, diagnosis and treatment initiation), identify bottlenecks and their reasons. We quantified patient preferences for a range of characteristics of health services using a discrete choice experiment (DCE) that assessed 7 attributes (distance, wait times, hours of operation, confidentiality, sex of provider, testing incentive, TB test speed and notification method).

RESULTS

Among 401 patients enrolled (median age of 34 years, 68.7% male, 46.6% HIV-positive), 60.9% and 39.1% were from a first-level and tertiary hospital, respectively. The median time from symptom onset to receipt of TB treatment was 5.0 weeks (IQR: 3.6-8.0) and was longer among HIV-positive patients seeking care at a tertiary hospital than HIV-negative patients (6.4 vs. 4.9 weeks, p = 0.002). The time from symptom onset to initial presentation for evaluation accounted for the majority of time until treatment initiation (median 3.0 weeks, IQR: 1.0-5.0)-an important minority of 11.0% of patients delayed care-seeking ≥8 weeks. The DCE found that patients strongly preferred same-day TB test results (relative importance, 37.2%), facilities close to home (18.0%), and facilities with short wait times (16.9%). Patients were willing to travel to a facility up to 7.6 kilometers further away in order to access same-day TB test results. Preferences for improving current TB services did not differ according to HIV status.

CONCLUSIONS

Prolonged intervals from TB symptom onset to treatment initiation were common, especially among PLHIV, and were driven by delayed health-seeking. Addressing known barriers to timely diagnosis and incorporating patients' preferences into TB services, including same-day TB test results, may facilitate earlier TB care engagement in high burden settings.

Delirium as a predictor of mortality and disability among hospitalized patients in Zambia

OBJECTIVE

To study the epidemiology and outcomes of delirium among hospitalized patients in Zambia.

METHODS

We conducted a prospective cohort study at the University Teaching Hospital in Lusaka, Zambia, from October 2017 to April 2018. The primary exposure was delirium duration over the initial 3 days of hospitalization, assessed daily using the Brief Confusion Assessment Method. The primary outcome was 6-month mortality. Secondary outcomes included 6-month disability, evaluated using the World Health Organization Disability Assessment Schedule 2.0.

FINDINGS

711 adults were included (median age, 39 years; 461 men; 459 medical, 252 surgical; 323 with HIV). Delirium prevalence was 48.5% (95% CI, 44.8%-52.3%). 6-month mortality was higher for delirious participants (44.6% [39.3%-50.1%]) versus non-delirious participants (20.0% [15.4%-25.2%]; P < .001). After adjusting for covariates, delirium duration independently predicted 6-month mortality and disability with a significant dose-response association between number of days with delirium and odds of worse clinical outcome. Compared to no delirium, presence of 1, 2 or 3 days of delirium resulted in odds ratios for 6-month mortality of 1.43 (95% CI, 0.73-2.80), 2.20 (1.07-4.51), and 3.92 (2.24-6.87), respectively (P < .001). Odds of 6-month disability were 1.20 (0.70-2.05), 1.73 (0.95-3.17), and 2.80 (1.78-4.43), respectively (P < .001).

CONCLUSION

Among hospitalized medical and surgical patients in Zambia, delirium prevalence was high and delirium duration independently predicted mortality and disability at 6 months. This work lays the foundation for prevention, detection, and management of delirium in low-income countries. Long-term follow up of outcomes of critical illness in resource-limited settings appears feasible using the WHO Disability Assessment Schedule.

Sarcoidosis around the Globe

Despite sarcoidosis having a worldwide occurrence, the epidemiological map still has gaps. Prevalence and incidence rates-inconsistences have been mainly due to a lack of uniformity in study definitions as well as data collection methods. Nonetheless, studies have been consistent in showing high prevalence and incidence in Scandinavian and African American populations. Data from racially diverse populations have consistently revealed highest incidence in people of African descent. Within populations, geographical (north-to-south gradient) and time clusters have also been demonstrated from place to place. Of great interest but still elusive to researchers is the cause of sarcoidosis. The most recent focus has mostly been on Mycobacteria species and Propionibacterium acnes, but results of research thus far have been less than outright and in some cases conflicting. Environmental exposures to such substances as mold and mildew and occupations such as agricultural employment, health care work, and firefighting have been widely cited as risk factors for diseases. Certain genotypes have been linked to sarcoidosis with familial and racial clusters apparent. Some disease phenotypes have also been linked to particular genes, leaving room for further genetic research. Sarcoidosis causes multisystemic morbidity, with pulmonary, cardiac, and neurological involvement carrying the worst prognosis. Disease phenotypes vary with ethnicity, suggesting a genetic predisposition; erythema nodosum is more common in Caucasian patients, cardiac manifestations in Japanese patients, and other extrathoracic disease in black patients.

Improving paediatric asthma care in Zambia

Problem

In 2008, the prevalence of paediatric asthma in Zambia was unknown and the national treatment guideline was outdated.

Approach

We created an international partnership between Zambian clinicians, the Zambian Government and a pharmaceutical company to address shortcomings in asthma treatment. We did two studies, one to estimate prevalence in the capital of Lusaka and one to assess attitudes and practices of patients. Based on the information obtained, we educated health workers and the public. The information from the studies was also used to modernize government policy for paediatric asthma management.

Local setting

The health-care system in Zambia is primarily focused on acute care delivery with a focus on infectious diseases. Comprehensive services for noncommunicable diseases are lacking. Asthma management relies on treatment of acute exacerbations instead of disease control.

Relevant changes

Seven percent of children surveyed had asthma (255/3911). Of the 120 patients interviewed, most (82/120, 68%) used oral short-acting β₂-agonists for symptom control; almost half (59/120, 49%) did not think the symptoms were preventable and 43% (52/120) thought inhalers were addictive. These misconceptions informed broad-based educational programmes. We used a train-the-trainer model to educate health-care workers and ran public awareness campaigns. Access to inhalers was increased and the Zambian standard treatment guideline for paediatric asthma was revised to include steroid inhalers as a control treatment.

Lessons learnt

Joint activities were required to change paediatric asthma care in Zambia. Success will depend on local sustainability, and it may be necessary to shift resources to mirror the disease burden.