Positional OSA is very prevalent and noted in almost 70% of our patients. Low snoring frequency was noted to be a positive predictor for positional OSA, contrarily to low mean oxygen saturation which was found to be a negative predictor. These findings are encouraging that positional therapy can be very beneficial as the treatment modality for OSA among Asians.

Introduction: Unlike Caucasians, many Asians with obstructive sleep apnea (OSA) are non-obese but are affected by the disease due to predisposing craniofacial structure. Therefore, non-obese and obese OSA may represent different disease entities. The associated risk factors for developing cardiovascular-related diseases, consequently, may be considered separately for the two types of OSA. Method: We reviewed polysomnographic studies performed in adults (aged ≥ 18 years) diagnosed with OSA (respiratory disturbance index [RDI] ≥ 5). We divided the patients into obese (body mass index [BMI] ≥ 25) and non-obese (BMI < 25) groups. We aimed to determine the differences between these two groups in terms of clinical presentations, polysomnographic fi ndings, and association with cardiovascular-related diseases including hypertension, diabetes mellitus, coronary artery disease, and/or cerebrovascular disease. Results: Among 194 patients with OSA (RDI ≥ 5), 63.4% were non-obese and 36.6% were obese. Compared with obese OSA patients, non-obese OSA patients were noted to have smaller neck size, less prevalence of hypertension, and less history of frequent nocturia (> 3-4/week), with equal prevalence of excessive daytime sleepiness. Overall, non-obese OSA patients were noted to have milder disease indicated by lower total, supine, and non-supine, NREM RDI and higher mean and nadir oxygen saturations. In the non-obese group, only total obstructive apnea index (OAI) was noted to be a predictor for developing any of the cardiovascular-related diseases after controlling for age, sex, and RDI (odds ratio = 9.7). However, in the obese OSA group, frequent snoring (> 50% of total sleep time), low sleep effi ciency (≤ 90%), and low mean oxygen saturation (< 95%) were noted to be signifi cant predictors of cardiovascular-related diseases (odds ratios = 12.3, 4.2, and 5.2, respectively). Conclusion: Among Asians, most OSA patients were not obese. Compared to obese OSA patients, non-obese OSA patients were noted to have less prevalence of hypertension and less history of nocturia. They were also noted to have overall milder OSA. Only OAI was noted to be a signifi cant predictor for cardiovascular-related disease in the non-obese OSA group. keywords: Obstructive sleep apnea, obesity Citation: Chirakalwasan N; Teerapraipruk B; Simon R; Hirunwiwatkul P; Jaimchariyatam N; Desudchit T; Charakorn N; Wanlapakorn C. Comparison of polysomnographic and clinical presentations and predictors for cardiovascular-related diseases between non-obese and obese obstructive sleep apnea among Asians. J Clin Sleep Med 2013;9(6):553-557.http://dx.doi.org/10.5664/jcsm.2748 S C I E N T I F I C I N V E S T I g A T I O N SO bstructive sleep apnea (OSA) is characterized by repetitive episodes of complete (apnea) or partial (hypopnea) upper airway obstruction occurring during sleep. These events often result in reduction in blood oxygen saturation and are usually terminated by brief arousals from sleep.1 Prior study has shown that obesity is one of the important ri...

Nasopharyngeal carcinoma (NPC) is among the commonest cancers in Malaysia. The prognosis for NPC like most other head and neck cancer is dependent on its staging. Majority of patients in Malaysia at the time of diagnosis are either at stage III or IV (27 and 47%, respectively). The lack of knowledge among primary care medical doctors regarding NPC may contribute to this delay in diagnosis. The aim of this study was to assess the knowledge of the primary care doctors in the state of Perak on the various aspects of NPC. The doctors at the primary care level in the state of Perak were recruited to take part in this study on a voluntary basis. A total number of 154 out of 198 doctors participated in this survey. They were given a questionnaire to fill in to test their knowledge on different aspects of NPC and its treatment. The overall respondents' score was poor with a score of 67.5% on all sections. The doctors appear to be able to identify common presenting features of NPC with a mean score of 85.3% but for the uncommon presentations of NPC, the scores were poorer with 61.8%. In addition, 54.1% of the participants answered that they would refer a patient with symptoms suspicious of NPC after a period of 1 month from the onset of symptom. However, only 34% would refer within 2 weeks. Based on the results of this study, the authors feel that it is clear that the doctors posted in the primary care hospitals and clinics appear to have inadequate knowledge to diagnose and refer patients with suspected NPC. As early diagnosis can often lead to a better prognostic outcome, steps must be taken to raise the awareness among these doctors.

Patients with any of the cardiovascular-related diseases are at a higher risk of having moderate to severe OSA without significant increase in daytime sleepiness. Therefore, we suggest that patients with any of the cardiovascular-related diseases should be screened for OSA, even if they are asymptomatic.

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