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  5. FP459 : Is Socioeconomic Status Associated with Severe Retinopathy of Prematurity in Preterm Infants

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Dr. Kshirsagar Sucheta, K08145, Dr. (Col.) Madan Deshpande, Dr. Kuldeep Dole, Dr. Khandekar Rajiv

Title:

Is Socioeconomic status of the parents associated with Severe Retinopathy of Prematurity in preterm infants?

Abstract:

Purpose:

This study was conducted with the purpose of understanding role of socioeconomic factors in health outcome in the form of severe ROP in preterm infants in western India.

Methods:

This case control type of observational study was conducted in a tertiary eye care center situated in an urban metropolitan area of western India in 2013. Cases were defined as preterm low birth weight infants with diagnosis of ‘Severe ROP’ (those requiring treatment). Controls comprised of preterm infants who did not develop severe ROP. Detail socioeconomic data based on Kuppuswamy scale were collected of each parent. Odds ratio for association between socioeconomic factors and severe ROP was calculated using a statistical tool. Multiple logistic regression analysis was performed to account for effect of potential confounders.

Results:

Total 44 cases and 104 controls could be enrolled for the study. Preterm infants whose mother was educated up to high school or less were at higher odds of developing severe ROP (OR 2.4, 0.9- 7.8). Rest of the factors such as mother’s occupation, father’s education and occupation, socioeconomic class of the family did not show any statistically significant association with severe ROP. The adjusted OR for association between mother’s education and severe ROP after multiple logistic regression analysis was 1.4 (0.6-14.5).

Conclusion:

Socioeconomic status of the parents is not associated with severe ROP in preterm low birth weight infants.

Introduction:

Retinopathy of prematurity (ROP) is a potentially blinding vaso-proliferative disorder of the retina seen in preterm low birth weight infants. It is emerging as an important cause of childhood blindness in middle income countries such as India. Blindness due to ROP is irreversible but largely preventable with timely screening and treatment. This blindness has been largely controlled in developed economies such as Western Europe and North America owing to excellent neonatal care practices and universal screening. In middle income countries such as India, ROP is emerging as an important cause of childhood blindness and this is termed as ‘third epidemic’ of ROP.1,2Low birth weight (BW), low gestational age (GA) and other systemic factors have been documented to be associated with ROP in India and elsewhere.3-5Socio-economic status of the family could be a major determinant of perinatal health outcomes in a child. A burgeoning volume of research identifies social factors at the root of much of the inequalities in health outcomes.6 Education and economic status of mother/ father of a child could affect their health seeking behavior and hence the care a preterm child may receive. In India 60% of the inpatient care is provided by private sector.7 In a private Neonatal Intensive Care Unit (NICU) where there is fees for the service, sick babies are likely to get better quality of care with close monitoring owing to optimal human resource.Parents from lower socioeconomic strataare likely to seek care in free public facilities which are oftenconstrained for human and other resources.8 This may have implications on the quality of care a preterm child may receive and the health outcomessuch as ROP. On the other hand ROP resulting in ‘lifetime of blindness’ in a preterm infant can have great socioeconomic impact on the family further pushing the family into cycle of poverty. To the best of the authors’ knowledge, there has not been any published study exploring association of socio-economic factors and severe ROP. This study was undertaken to find association between severe ROP and education, occupation and socioeconomic class of the parents. Based on the findings, recommendationscould be made to formulate strategies in such a way that risk of poor outcome in preterm children from low socioeconomic background could be reduced.

Methods:

This case control type of observational study was conducted in a tertiary eye care center situated in an urban metropolitan area of western India in 2013. Parents of children enrolled in ROP screening program of the study hospital were invited to participate when they visited study hospital for follow up screening. The parents were invited to participate in the study after final decision of whether the child was going to require treatment (case) or was to be discharged from ROP follow up (control) was taken. The population of preterm children came from multiple NICUs (both public and private sector).

Ethics approval:

Ethics approval for the study was obtained from the institutional ethics committee. Written informed consent was obtained from one of the parents after explaining the purpose of the study. The study abided by the tenets of Helsinki.

Cases and controls:

Cases were preterm children with diagnosis of ‘Severe ROP’ (those at risk of blindness or severe visual impairment). Severe ROP was defined as treatment requiring ROP. Controls comprised of preterm infants who did not develop severe ROP (hence not at risk of blindness from ROP).

International Classification of ROP was used for diagnosis.9 Guidelines from Early Treatment for ROP (ETROP)10 group were used to decide whether treatment was required or not for a particular child.

Sample size calculation: To calculate the sample size, it was assumed that 70% of cases would belong to lower socioeconomic class compared to 40% controls. To achieve 95% confidence interval and 80% power to detect the difference, 45 cases were needed. Two controls were recruited for each case.Both cases and controls were recruited from the infant population enrolled in ROP program of the study hospital when they visited the study hospital for follow up visits. The cases and controls came from both private and public sector NICU). Equal distribution of cases and controls between private and public sector was ensured to minimize selection bias.

Data on socioeconomic variables were collected by field staff who were not aware of the study hypothesis. This was ensured to minimize information bias.Data were collected on each parent’s education, occupation and monthly family income. Kuppuswamy socioeconomic scale was used to classify family into one of the 5 socioeconomic levels.11For analysis purpose education, occupation, socioeconomic class were divided into 2 categories as shown in Table 1.

Category 1 was considered as the ‘exposure’ or ‘risk factor’ for severe ROP.

Data on potential confounders such as birth weight, gestational age, any illness during NICU stay (such as oxygen supplementation, sepsis, respiratory distress syndrome, anemia, blood transfusion etc) were collected. All the data were entered in a Microsoft excel sheet and analyzed using a statistical software (SSPS). Odds ratio (OR) for each of the socioeconomic variables of mother and father were calculated using Pearson’s chi square test. Multiple logistic regression analysis was done for calculating Odds ratio after taking into account effect of confounding variables. The variables used for multiple logistic regression analysis were- GA, BW, oxygen supplementation, respiratory distress syndrome, sepsis, anemia, blood transfusion, apneic spells, phototherapy for neonatal jaundice. All of these are known to be risk factors for development of ROP.

Results:

Total 44 cases (private: public sector= 1:1) and 104 controls (private sector-50, public sector-52) could be recruited for the study.

Males constituted 54.5% (24/44) of cases and 51.9% (54/104) of controls.

Mean GA in cases was 29.6 weeks (range 25 – 34) whereas that in controls was 31.2 weeks (range 28 – 35).

Mean BW recorded in cases was 1157 grams (range 692 -1925), whereas that recorded in controls was 1376 grams (range 700 – 2310).

Association between Mother’s education and severe ROP:

Table 2 shows distribution of cases and controls by mother’s education. Odds Ratio (OR) for occurrence of severe ROP in preterm children belonging to mothers educated up to high school or less was 2.4 (95% CI 0.9-7.8), (P- 0.06)

Similarly OR was calculated for association between other socioeconomic variables such as- father’s education, occupation, mother’s occupation and socioeconomic class of the family and severe ROP. Table 3 depicts association between these socioeconomic variables and severe ROP with corresponding ORs for each variables.

Multiple logistic regression analysisfor association between mother’s education and severe ROP after accounting for other risk factors for ROP showed an OR of 1.4 (0.6-14.5, P- 0.1).

Discussion:

Kuppuswamy’s socioeconomic scale has been successfully used in the past to determine risk factors of various diseases in children.12-14 The socioeconomic scale was used to explore association of socioeconomic factorsand corneal pathologies needing keratoplasty by Dada et al.15 To the best of authors’ knowledge, attempt to link this scale to ROP is being done for the first time.

There was some suggestive evidence that preterm children whose mothers were educated up to high school or less were 2.4 times more likely to have severe ROP. This could be because an educated mother is more likely to be aware or perceptive towards health care practices such as hand washing before touching the child, breast feeding etc. These practices are known to reduce the risk of severe ROP by preventing illness in a preterm child. Better the general health of the child, less is the risk of ROP. Educated mother is also likely to be different in her health seeking behavior and more likely to come back for follow up screening.

However, the association of severe ROP with mother’s education attenuated after taking into account effect of other risk factors for ROP. Hence in conclusion, occurrence of severe ROP among preterm children in urban metropolitan area of western India was not associated with socioeconomic status of parents.

There are certain limitations of this study. The study population came from an urban metropolitan city where coverage and access to health facilities is better than that in semi urban or rural areas. Hence the findings of this study may be biased and not generalizable. A similar study conducted in semi urban or rural areas where neonatal care has been expanding rapidly in the past decade might have fetched different results especially due to stark differences in socioeconomic status of people living in urban and rural India. Mothers with poor socioeconomic status are likely to have low maternal weight gain, suffer from anemia, less likely to have hospital delivery therefore increasing chances of early deathof the child before development of severe ROP.There is also a possibility that parents from lower socioeconomic class may miss screening for ROP on account of various barriers such as lack of awareness, distance, cost, transport etc. Such children may not be detected despite having severe ROP. These factors could likely have resulted in underestimation of the strength of association between socioeconomic class and severe ROP.Study with larger sample size is required to confirm the strength of association of socioeconomic status of family and severe ROP in a preterm child. However, based on the findings from this study- It is recommended that ROP screening be practiced universally in India, as the risk of severe ROP does not differ by socioeconomic class of the parents.

References:

  1. Blencowe, H., Lawn, J. E., Vazquez, T. et al. Preterm-associated visual impairment and estimates of retinopathy of prematurity at regional and global levels for 2010. Pediatr Res74 Suppl 1, 35-49, doi:https://dx.doi.org/10.1038/pr.2013.205 (2013).
  2. Blencowe H, M. S., Gilbert C. Update on Blindness Due to Retinopathy of Prematurity Globallyand in India. Indian PediatricsVolume 53, Supplement 2. , 2016, 89-92 (2016).
  3. Chaudhari, S., Patwardhan, V., Vaidya, U. et al. Retinopathy of prematurity in a tertiary care center–incidence, risk factors and outcome. Indian pediatrics46, 219 (2009).
  4.   Clare Gilbert, A. F., Luz Gordillo,Graham Quinn, Renato Semiglia, Patricia Visintin,  on behalf of the International NO-ROP Group. Characteristics of babies with severe retinopathy of prematurity in countries with low, moderate and high levels of development: implications for screening programmes. Pediatrics115, 518-525 (2005).
  5. Hungi, B., Vinekar, A., Datti, N. et al. Retinopathy of Prematurity in a rural Neonatal Intensive Care Unit in South India–a prospective study. Indian J Pediatr79, 911-915, doi:https://dx.doi.org/10.1007/s12098-012-0707-y (2012).
  6. Michael Marmot. Social determinants of health inequalities. Lancet;365:, 1099–1104 (2005).
  7. Reddy, K. S. India’s Aspirations for Universal Health Coverage. N Engl J Med373, 1-5 (2015).
  8. Balarajan, Y., Selvaraj, S. & Subramanian, S. V. Health care and equity in India. Lancet377, 505-515, doi:10.1016/S0140-6736(10)61894-6 (2011).
  9. International Committee for the Classification of Retinopathy of, P. The International Classification of Retinopathy of Prematurity revisited. Arch Ophthalmol123, 991-999 (2005).
  10. Early Treatment for Retinopathy of Prematurity Cooperative Group. Revised indications for the treatment of retinopathy of prematurity: results of the early treatment for retinopathy of prematurity randomized trial. Arch Ophthalmol121, 1684-1694, doi:10.1001/archopht.121.12.1684 (2003).
  11. Sharma, R. Kuppuswamy’s Socioeconomic Status Scale – Revision for 2011 and Formula for Real-Time Updating. The Indian Journal of PediatricsVolume 79, 961–962 (2012).
  12. Mughal, A. R., Sadiq, M., Hyder, S. N. et al. Socioeconomic status and impact of treatment on families of children with congenital heart disease. J Coll Physicians Surg Pak21, 398-402, doi:07.2011/JCPSP.398402 (2011).
  13. Sulagna Mitra, S. B. The impact of pediatric nephrotic syndrome on families. Pediatr Nephrol 26, 1235 ( 2011).
  14. V. GOPICHANDRAN, P. C., L. S. BABY, & A. FELINDA, V. R. M. Household food security in urban Tamil Nadu: a survey in Vellore. Natl Med J India.23, 278-280 (2010).
  15. Dada, T., Sharma, N. & Vajpayee, R. B. Indications for pediatric keratoplasty in India. Cornea18, 296-298 (1999).

Table 1: Categories of socioeconomic variables

Variables Category 1 Category 2
Education Up to high school More than high school
Occupation Up to skilled worker More than skilled worker
Socioeconomic class Lower middle or lower Upper middle or higher

 

Table 2: Association between mother’s education and severe ROP

Up to High school (%) More than High school (%) Total
Cases 38 (33.6) 6 (17.2) 44
Controls 75 (66.3) 29 (82.8) 104
Total 113 (100) 35 (100) 148

(P- 0.06)

 

Table 3: Association between other socio economic variables and severe ROP

Variable Odds Ratio 95% CI P value
Occupation- Mother 1.3 0.3-5.8 0.6
Education- Father 1.5 0.6-3.7 0.3
Occupation- Father 0.6 0.3-1.4 0.2
Socioeconomic class-Family 1.2 0.5-2.7 0.6

 

 

 

 

 

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