Are we making good use of our public resources? The false-positive rate of screening by fundus photography for diabetic macular oedema.

INTRODUCTION: A large proportion of patients diagnosed with diabetic maculopathy using fundus photography and hence referred to specialist clinics following the current screening guidelines adopted in Hong Kong and United Kingdom are found to be false-positive, implying that they did not have macular oedema. This study aimed to evaluate the false-positive rate of diabetic maculopathy screening using the objective optical coherence tomography scan. METHODS: This was a cross-sectional observational study. Consecutive diabetic patients from the Hong Kong West Cluster Diabetic Retinopathy Screening Programme with fundus photographs graded R1M1 were recruited between October 2011 and June 2013. Spectral-domain optical coherence tomography imaging was performed. Central macular thickness of ≥300 µm and/or the presence of optical coherence tomography signs of diabetic macular oedema were used to define the presence of diabetic macular oedema. Patients with conditions other than diabetes that might affect macular thickness were excluded. The mean central macular thickness in various subgroups of R1M1 patients was calculated and the proportion of subjects with central macular thickness of ≥300 µm was used to assess the false-positive rate of this screening strategy. RESULTS: A total of 491 patients were recruited during the study period. Of the 352 who were eligible for analysis, 44.0%, 17.0%, and 38.9% were graded as M1 due to the presence of foveal 'haemorrhages', 'exudates', or 'haemorrhages and exudates', respectively. The mean (±standard deviation) central macular thickness was 265.1±55.4 µm. Only 13.4% (95% confidence interval, 9.8%-17.0%) of eyes had a central macular thickness of ≥300 µm, and 42.9% (95% confidence interval, 37.7%-48.1%) of eyes had at least one optical coherence tomography sign of diabetic macular oedema. For patients with retinal haemorrhages only, 9.0% (95% confidence interval, 4.5%-13.5%) had a central macular thickness of ≥300 µm; 23.2% (95% confidence interval, 16.6%-29.9%) had at least one optical coherence tomography sign of diabetic macular oedema. The false-positive rate of the current screening strategy for diabetic macular oedema was 86.6%. CONCLUSION: The high false-positive rate of the current diabetic macular oedema screening adopted by the United Kingdom and Hong Kong may lead to unnecessary psychological stress for patients and place a financial burden on the health care system. A better way of screening is urgently needed. Performing additional spectral-domain optical coherence tomography scans on selected patients fulfils this need.

Outcomes after oesophageal perforation: a retrospective cohort study of patients with different aetiologies.

INTRODUCTION: The mortality rate after oesophageal perforation is high despite advances in operative and non-operative techniques. In this study, we sought to identify risk factors for hospital mortality after oesophageal perforation treatment. METHODS: We retrospectively examined patients treated for oesophageal perforation in a university teaching hospital in Hong Kong between January 1997 and December 2013. Their demographic and clinical characteristics, aetiology, management strategies, and outcomes were recorded and analysed. RESULTS: We identified a cohort of 43 patients treated for perforation of the oesophagus (28 men; median age, 66 years; age range, 30-98 years). Perforation was spontaneous in 22 (51.2%) patients (15 with Boerhaave's syndrome and seven with malignant perforation), iatrogenic in 15 (34.9%), and provoked by foreign body ingestion in six (14.0%). Of the patients, 14 (32.6%) had pre-existing oesophageal disease. Perforation occurred in the intrathoracic oesophagus in 30 (69.8%) patients. Emergent surgery was undertaken in 23 patients: 16 underwent primary repair, six surgical drainage or exclusion, and one oesophagectomy. Twenty patients were managed non-operatively, 13 of whom underwent stenting. Two stented patients subsequently required oesophagectomy. Four patients had clinical signs of leak after primary repair: two were treated conservatively and two required oesophagectomy. Overall, six (14.0%) patients required oesophagectomy, one of whom died. Nine other patients also died in hospital; the hospital mortality rate was 23.3%. Pre-existing pulmonary and hepatic disease, and perforation associated with malignancy were significantly associated with hospital mortality (P=0.03, <0.01, and <0.01, respectively). CONCLUSIONS: Most oesophageal perforations were spontaneous. Mortality was substantial despite modern therapies. Presence of pre-existing pulmonary disease, hepatic disease, and perforation associated with malignancy were significantly associated with hospital mortality. Salvage oesophagectomy was successful in selected patients.

Screening for retinopathy of prematurity and treatment outcome in a tertiary hospital in Hong Kong.

INTRODUCTION: Studies on the prevalence and severity of retinopathy of prematurity in the local population are scarce. This study aimed to evaluate the prevalence, screening, and treatment outcome of retinopathy of prematurity in a tertiary hospital in Hong Kong. METHODS: This cross-sectional study with internal comparison was conducted at Queen Mary Hospital, Hong Kong. The study evaluated 89 premature infants who were born at the hospital and were screened for retinopathy of prematurity, in accordance with the 2008 British Guidelines, between January 2013 and December 2013. The prevalences of retinopathy of prematurity and severe retinopathy requiring treatment were studied. RESULTS: The mean (± standard deviation) gestational age at birth was 30+2 weeks ± 16.5 days (range, 24+1 to 35+5 weeks). The mean birth weight was 1285 g ± 328 g (range, 580 g to 2030 g). A total of 15 (16.9%) infants developed retinopathy of prematurity and three (3.4%) required treatment. In a subgroup analysis of extremely-low-birth-weight infants of <1000 g, 70.6% developed retinopathy of prematurity and 17.6% required treatment. Multivariate logistic regression analysis suggested low birth weight and patent ductus arteriosus were significantly associated with development of retinopathy of prematurity (P<0.001 and P=0.035, respectively). Among the three infants who received treatment for severe retinopathy of prematurity, all regressed successfully after one laser treatment. CONCLUSIONS: Retinopathy of prematurity is a significant problem among premature infants in Hong Kong, especially those with extremely low birth weight. Our screening service for retinopathy of prematurity was satisfactory and treatment results were good. Strict adherence to international screening guidelines and vigilance in infants at risk are key to successful management of retinopathy of prematurity.

Associations between diabetic retinopathy and systemic risk factors.

INTRODUCTION: Diabetes mellitus is a systemic disease with complications that include sight-threatening diabetic retinopathy. It is essential to understand the risk factors of diabetic retinopathy before effective prevention can be implemented. The aim of this review was to examine the association between diabetic retinopathy and systemic risk factors. METHODS: A PubMed literature search was performed up to May 2016 to identify articles reporting associations between diabetic retinopathy and systemic risk factors; only publications written in English were included. Relevant articles were selected and analysed. RESULTS: Patients with diabetic retinopathy were more likely to have poor glycaemic control as reflected by a higher glycated haemoglobin, longer duration of diabetes, and use of insulin therapy for treatment. For other systemic risk factors, hypertension was positively associated with prevalence and progression of diabetic retinopathy. No clear association between obesity, hyperlipidaemia, gender, or smoking with diabetic retinopathy has been established as studies reported inconsistent findings. Myopia was a protective factor for the development of diabetic retinopathy. Several genetic polymorphisms were also found to be associated with an increased risk of development of diabetic retinopathy. CONCLUSIONS: Good glycaemic and blood pressure control remain the most important modifiable risk factors to reduce the risk of progression of diabetic retinopathy and vision loss.