Discussion
Although the true prevalence of DR in Myanmar is unknown, an unusually high prevalence of vision -threatening DR was found in our study patients (23.5%). In comparison, a systematic review and meta-analysis of seven studies in the neighbouring country of India revealed a pooled prevalence of DR of 14.8% in patients age 30 and over and 18.1% in patients 50 and older.11
The results of this study highlight the underdiagnosis, delayed diagnosis, and undertreatment of both DM and DR in Myanmar. For example, PRP was performed for vision-threatening DR in 16% of those whose DM had been diagnosed within just 1 year. This fact is remarkable since DR is an advanced complication that only occurs many years after the onset of DM. Thus, delayed treatment of vision-threatening DR can result from either delayed diagnosis of DM or from delayed diagnosis of DR in known diabetics. Additionally, because there is limited treatment beyond metformin available to most diabetics in Myanmar, increased diabetic complications, including DR, are to be expected as a result of such undertreatment.
Hypertension was a significant risk factor for the development of vision-threatening DR in this group of patients. Patients who were diabetic with hypertension were more likely to require PRP than patients who were diabetic without hypertension (p value 0.01), and there was a strong trend correlation with grade of hypertension (p value 0.003). It is known that the incidence of DR is influenced by several important risk factors: poor blood glucose control, delay in diagnosis of DM, high blood pressure, obesity and smoking. A National STEPS Survey in 2009 in Myanmar recorded these significant risk factors: the prevalence of hypertension was 31.0% in males and 29.3% in females.12 Given the high correlation to the spot blood pressure, screening/treatment programs may add extra checkpoints to identify and treat higher-risk individuals and to reduce diabetic complications.
Although vision loss and blindness due to DM is to a large extent preventable with proper care, access to such care in Myanmar is difficult or impossible for most diabetics. Some of these access problems are unique to Myanmar, some not. It is a country made up of 135 national races speaking over 100 languages and dialects and thus has unique challenges due to administrative and cultural divisions. In addition, many people are prevented from accessing medical care by work obligations, personal financial straits, severe weather and transportation difficulties. For these and other reasons, many diabetics have historically turned to traditional forms of healing13 rather than seeking care from the medical system. Finding ways to address these obstacles, as well as developing a strong educational campaign to improve awareness of the dangers of DR,14 are therefore prerequisites to the success of a broad-based screening/treatment programme.
Another major obstacle to improving diagnosis and treatment of DR in Myanmar is a shortage of ophthalmologists. There are just 309 ophthalmologists to serve the 60 million people in Myanmar.15 These ophthalmologists are not able to keep up with the backlog of patients who need cataract surgery, much less keep up with the growing need for treatment of vision-threatening DR. A further impediment is the marked imbalance in the distribution of ophthalmologists between the biggest cities and the rest of the country. The two largest cities, Yangon and Mandalay, have 60% of the country’s ophthalmologists, but only about 25% of the country’s population.15 That means for the 45 million people outside of Yangon and Mandalay, there are only 123 ophthalmologists. If Myanmar is to develop an effective programme to prevent blindness from DR, its goals should be to train more ophthalmologists and to dedicate more resources to establish a robust screening/treatment programme throughout the country. The significant prevalence of other eye pathology in these study patients demonstrates an additional value of such a screening programme.
There are limitations to this pilot study, most notably its small size. In addition, the study was carried out at a single hospital with patients referred by local doctors. This referral process could cause selection bias towards more severe disease. Nevertheless, this pilot study demonstrated a rate of DR (37%) in line with that found around the world (34%).16 However, the rate of vision-threatening DR among those with DR (64%) in our study population was much greater than commonly reported (33%).16 This higher than expected rate of vision-threatening DR should therefore be investigated with larger studies. Additionally, given the large and growing number of diabetics in Myanmar, the design of future studies of DR prevalence in Myanmar should take into consideration all current local and regional data.
This pilot study demonstrates the feasibility of locating and treating patients with vision-threatening DR in a provincial area of Myanmar despite the obstacles particular to the country. These results are important because there is at present very inadequate screening/treatment for DR in Myanmar. They suggest that such screening/treatment, if expanded throughout the country, could greatly reduce the burden of diabetic blindness for individuals and for society in general. This pilot study also provides data that can help in the design of a larger cross-sectional study of the prevalence of DR in Myanmar.