Overnight pulse oximetry for screening of obstructive sleep apnea in at-risk adult patients in the primary care setting:prospective case series

Objective:To estimate prevalence of OSA among at risk adult patients in primary care setting.To test the correlation and agreement between overnight pulse oximetry and polysomnography(PSG).To test the OSA screening performance of overnight pulse oximetry.Design and Setting:Prospective case series involving adult Chinese patients with risk fac-tors for OSA at a primary care clinic of Hong Kong.Methods:The prevalence and severity of OSA were established based on overnight pulse oximetry derived oxygen desaturation index(ODI).Screening performance of overnight pulse oxi-metry was compared directly with gold standard diagnostic test PSG.Results:Three hundred and five male and 229 female patients were recruited.Snoring(48.3%)was the top presenting symptom.Three hundred and twenty five patients(60.9%)were screened positive to have OSA.One hundred and nine patients had performed PSG,the ODI_4 and apnoea-hypopnea index(AHI)had Pearson correlation coefficient 0.71(P<0.001).Bland and Alt-man plot showed good agreement.Using designation criteria of ODI_4≥5 events/hr,the sensitivity and specificity for OSA diagnosis are 94.4%and 78.9%respectively.Conclusion:The prevalence of OSA is 60.9% among adult primary care population who are at risk for OSA.Overnight pulse oximetry shows good performance as a screening tool for the screening of OSA.

Epidemiological study of hypertensive retinopathy in the primary care setting: Retrospective cross-sectional review of retinal photographs

Objective:The objective is to estimate the prevalence and grading of hypertensive retinopa-thy in the primary care setting;examine the patient characteristics associated with hypertensive retinopathy;and examine the association of hypertensive retinopathy and other hypertension complications.Methods:This is a retrospective cross-sectional study.Subjects included adult hypertensive patients with available and gradable retinal photographs.Results:Two hundred fifty-six male hypertensive patients(34.3%)and 491 female hyper-tensive patients(65.7%)were included.The average duration of hypertension was 7.2 years,and 49.8%and 41.2%of patients were taking one or two antihypertensive medications respectively.Among 1491 qualified retinal photographs(744 right eye and 747 left eye),24.9%,62.6%,and 12.5%were classified as showing normal,mild,and moderate hypertensive retinopathy respec-tively.The three commonest retinal signs were generalized or focal arteriolar narrowing(650 cases,43.6%),hard exudates(168 cases,11.3%),and opacity(copper or silver wiring)of the arteriolar wall(166 cases,11.1%).Patients older than 61 years,having hypertension for more than 15 years,or taking three or more antihypertensive medications were significantly associated with hyperten-sive retinopathy(P<0.05).Conclusion:In a primary care clinic in Hong Kong,77.1%of hypertensive patients had hypertensive retinopathy.Advanced hypertensive retinopathy was the commonest target organ damage for hypertensive patients in a primary care clinic.