View clinical trials related to Observation.
Filter by:Apart from obesity, craniofacial factors are well recognized in the pathogenesis of obstructive sleep apnea (OSA) and are likely to play an important role in influencing the response to weight loss. The prevalence of OSA syndrome is as common among the middle-aged Hong Kong Chinese populations as the Caucasians, despite our Chinese patients having much lower body mass index (BMI). From previous work on ethnic comparison, for the same degree of OSA severity, Caucasians were more overweight, whereas Chinese exhibited more craniofacial bony restriction. Cephalometric measurements based on lateral radiograph of the upper airway have shown that a shorter distance between maxillary projection from the cranial base, a smaller posterior airway space, less mandibular protrusion, a narrower space between the hard palate and cranial base, and a more caudally placed hyoid bone predispose to a higher apnea-hypopnea index (AHI). A recent study shown that a shorter mandibular length as measured by lateral cephalometry was associated with a greater fall in AHI after weight loss. Another study using craniofacial computed tomography (CT) scans to evaluate the maxillomandibular bony volume found that craniofacial restriction influenced the relationship between weight loss and OSA improvement. Collectively, these studies suggest that the effect on AHI with weight loss is likely to be more pronounced in those with a smaller craniofacial skeleton. However, the effect of the craniofacial restriction on the degree of rebound in OSA following weight gain after the weight loss intervention is unknown. The study aims to investigate the change in weight and OSA severity following cessation of a lifestyle modification program (LMP) and examine the relationship between craniofacial restriction and the degree of OSA reoccurrence.
This is an observational study using Bronchial-alveolar lavage (BAL) as specimen for GeneXpert, a real time polymerase chain reaction (PCR) test for detection of tuberculosis (TB). Patients suspicious of TB, who require bronchoscopy as part of the investigation procedures, will be recruited for this study over a period of 18 months. Clinical likelihood of TB will be systematically scored according to various clinical parameters. This will determine the pre-test probability. Clinician will decide if anti-TB treatment is to be started and patients will be followed up for a minimal of 18 months. Sensitivity, specificity, positive, negative predictive values and the respective likelihood ratio will be calculated accordingly.