Prevalence, patterns, and risk factors of retinopathy of prematurity in a tertiary care multispecialty hospital in North Karnataka

Vishalakshi Bhat; Shankargouda H Patil; S Ashwini

doi:10.4103/jcor.jcor_24_22

ORIGINAL ARTICLE

Year : 2022 | Volume : 10 | Issue : 3 | Page : 114-117

Prevalence, patterns, and risk factors of retinopathy of prematurity in a tertiary care multispecialty hospital in North Karnataka

Vishalakshi Bhat¹, Shankargouda H Patil¹, S Ashwini²
¹ Department of Ophthalmology, SDM College of Medical Sciences and Hospital, Shri Dharmasthala Manjunatheshwara University, Dharwad, Karnataka, India
² Department of Community Medicine, SDM College of Medical Sciences and Hospital, Shri Dharmasthala Manjunatheshwara University, Dharwad, Karnataka, India

Date of Submission	05-Feb-2022
Date of Decision	29-Mar-2022
Date of Acceptance	11-Jul-2022
Date of Web Publication	1-Dec-2022

Correspondence Address:
Vishalakshi Bhat
Department of Ophthalmology, Shri Dharmasthala Manjunatheshwara College of Medical Sciences and Hospital, Shri Dharmasthala Manjunatheshwara University, Dharwad - 580 021, Karnataka
India

Source of Support: None, Conflict of Interest: None

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DOI: 10.4103/jcor.jcor_24_22

Abstract

Purpose: The purpose of this study was to study the patterns, prevalence, and risk factors which contribute to the development of retinopathy of prematurity (ROP) in a tertiary care multispecialty hospital. Materials and Methods: This was a retrospective study from April 2019 to March 2021. All the infants screened at our hospital for ROP as per the Government of India “Rashtriya Bal Swasthya Karyakram” guidelines were included. Baseline characteristics, systemic risk factors, and ocular findings including ROP stages and zones involved were noted in the designated pro forma. Statistical analysis was done using SPSS version 25 software. Results: Of the 604 eyes of 302 infants screened, 27.8% had ROP. The mean gestational age (GA) and birth weight were 32⁺⁵ ± 2⁺¹ weeks and 1.46 ± 0.39 kg, respectively. Among the 160 eyes with ROP, 44 eyes (27.5%) had Stage I ROP in Zone I, 57 eyes (35.6%) had Stage II ROP in Zone II, 17 eyes had Stage III (10.7%) ROP in Zone I and Zone II, and 42 eyes (26.25%) had aggressive posterior ROP (APROP). None had Stage IV or V ROP. GA <34 weeks, presence of blood transfusion, apnea, intraventricular hemorrhage (IVH), anemia, respiratory distress syndrome (RDS), and presence of two or more risk factors were positively associated with the development of ROP. Conclusion: The rate of ROP in our hospital is comparable to previously published data. A high rate of APROP was noted among the eyes developing ROP. Low GA and the presence of apnea, IVH, anemia, and RDS were associated with an increased chance of developing ROP.

Keywords: Patterns of retinopathy of prematurity, retinopathy of prematurity, risk factors for retinopathy of prematurity

How to cite this article:
Bhat V, Patil SH, Ashwini S. Prevalence, patterns, and risk factors of retinopathy of prematurity in a tertiary care multispecialty hospital in North Karnataka. J Clin Ophthalmol Res 2022;10:114-7

How to cite this URL:
Bhat V, Patil SH, Ashwini S. Prevalence, patterns, and risk factors of retinopathy of prematurity in a tertiary care multispecialty hospital in North Karnataka. J Clin Ophthalmol Res [serial online] 2022 [cited 2023 Mar 24];10:114-7. Available from: https://www.jcor.in/text.asp?2022/10/3/114/362503

Retinopathy of prematurity (ROP) is an emerging cause of blindness among preterm neonates. Every year around 15 million babies are born preterm in the world, with India in the top ten countries with the greatest number of preterm births.^[1] Improved survival of these babies is associated with an increase in the rate of ROP. The babies in developing countries do not show similar patterns of presentations of ROP as in developed nations.^[2] The patterns of ROP within a large country like ours vary from one region to another, possibly due to various antenatal and postnatal practices. Our hospital caters to the population of North Karnataka, which is a varied mixture of urban and rural populations. There is a need to study the patterns of ROP and prevalence in our hospital, which is a referral center for sick and high-risk babies from surrounding areas of North Karnataka. This study is designed to study the prevalence of ROP in our hospital, the patterns of presentation, and the various risk factors associated with the development of ROP.

Materials and Methods

This was a retrospective, observational study. The institutional ethical committee clearance was obtained for the study. Data analysis of records of all babies screened for ROP in the hospital between April 2019 and March 2021 was done. ROP screening was performed with an indirect ophthalmoscope with a 20 D lens, according to the guidelines for universal eye screening in newborns including ROP as per the Government of India (“Rashtriya Bal Swasthya Karyakram” June 2017).^[3] All the preterm babies who fulfilled the criteria of <34 weeks gestational age (GA) and birth weight <2 kg were screened 3–4 weeks after birth. Those with birth weight >2 kg and GA >34 weeks were included if the neonate had the presence of other risk factors such as respiratory distress, need for mechanical ventilation, septicemia, blood transfusion, and apnea. Data recorded were name, sex, GA at birth, birth weight, age, and weight at the time of screening and risk factors including respiratory distress syndrome (RDS), septicemia, blood transfusion, multiple gestations, apnea, intraventricular hemorrhage (IVH), anemia, hypoxia, and patent ductus arteriosus (PDA). ROP screening findings were documented in a designated pro forma and classified according to the revised International Classification of Retinopathy of prematurity classification.^[4] Further follow-up and treatment if required were done based on the severity noted during the examination as per the early treatment for ROP guidelines.^[5]

Data collected were entered into a Microsoft Excel sheet and subjected to statistical analysis with SPSS (Statistical Package for Social Sciences) Statistics for Windows, version 25.0 (IBM Corp., Armonk, N. Y., USA). Measures of central tendencies and dispersions were calculated where applicable. Chi-square test was used for analyzing associations between risk factors and the presence of ROP. A P < 0.05 was considered statistically significant.

Results

During the study period from April 2019 to March 2021, a total of 604 eyes of 302 babies were screened for ROP. Of the 302 infants, 188, i.e., 62.25% received first screening in the neonatal intensive care unit (NICU) before discharge. The mean GA of the infants screened was 32⁺⁵ ± 2⁺¹ weeks (range from 26⁺⁶ to 40 weeks). The mean birth weight of the infants was 1.46 ± 0.39 kg (range from 0.70 to 3.40 kg). Males were 161 (53.3%) and females were 141 (46.68%) in number. Of the 604 eyes screened, 160 eyes of 84 babies had some form of ROP (27.8%). The baseline characteristics of all the infants and those with ROP are shown in [Table 1]. Among the 160 eyes with ROP, 44 eyes (27.5%) had Stage I ROP in Zone II, 57 eyes (35.6%) had Stage II ROP in Zone II, 17 eyes had Stage III ROP (10.7%), 4 eyes had Stage III ROP in Zone I, and 13 eyes having Stage III ROP in Zone II. Forty-two eyes (26.25%) had aggressive posterior ROP (APROP) showing indistinct ROP stage with looping, shunting, and flat neovascular fronds in Zone I and posterior Zone II with vessel dilation and tortuosity in all quadrants (plus disease). One infant had a plus disease associated with Stage II ROP in Zone II. A total of 60 eyes (including 18 with Type I ROP^[5] and 42 with APROP) of 31 infants needed treatment. The 21 infants diagnosed with APROP had bilateral disease, with neovascularization of the iris noted in 28 eyes of 14 infants. None of our subjects had Stage IV or Stage V ROP at the time of screening or till the last available follow-up.

Table 1: Baseline characteristics of all the screened infants and those with retinopathy of prematurity

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The various risk factors associated with the presence of ROP were analyzed. Positive association of developing ROP was seen with GA <34 weeks, presence of packed red blood cell transfusion, apnea, IVH, anemia, RDS, and presence of two or more risk factors. Septicemia, multiple gestation, hypoxia, and PDA had no statistically significant association with the development of ROP. Birth weight and development of ROP had no statistically significant association in our study. Of the 302 babies screened, 283 weighed <2 kg at birth. Eighty (28.26%) infants of these developed ROP. Of the 19 infants with a birth weight of more than 2 kg, four infants (21.05%) developed ROP. Chi-square test showed a P = 0.83, which was not significant. [Table 2] shows the association of different risk factors with the development of ROP.

Table 2: The number of infants with risk factors (with percentages) with and without retinopathy of prematurity and their associations

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If western standards for screening infants <1500 g birth weight and <32 weeks GA are applied to our subjects, 21 infants (25%) with ROP would be outside the birth weight screening cut-off of 1500 g and 28 infants (33.33%) with ROP would be outside the GA criteria of 32 weeks.

Discussion

Our study was done in a tertiary care hospital in North Karnataka and shows the prevalence and patterns of ROP in our hospital. It also determines the associations of various risk factors with the development of ROP.

The rate of ROP in our study is 27.8%. This is comparable to the varying rates of ROP ranging from 20% to 40%, reported from different centers in India.^[6],[7] Sixty eyes (9.9%) of 31 infants had severe ROP requiring treatment. The rate of severe ROP is also variable in different parts of India. Dwivedi et al. have reported an incidence of 14% severe ROP in their study done in Eastern Madhya Pradesh.^[8] Hungi et al. have reported an incidence of 10.2% severe ROP in their study done in a rural NICU.^[9] Ahuja et al. who studied the risk factors for ROP in a Southern Indian district have reported a rate of 13.2%.^[10] These rates are much higher when compared to those reported from different centers by Kumar et al. (4.7%) and Vinekar et al. (3.5%).^[11],[12] This points toward the variable neonatal practices in different centers in India, indicating a need for better, improved NICU practices and protocol-based treatment approaches in these infants.

Forty-two eyes (26.25%) out of 160 eyes with ROP had APROP, which is very high compared to other reports. Hungi et al. have reported 13.2% of their cases to be APROP.^[9] The rates of APROP differ markedly from other reports from different parts of the country.^[13],[14] Five infants had been referred to our center for management of APROP and NICU care, which contributed to 10 eyes with APROP. Our NICU is a referral center in North Karnataka for sick preterm infants from surrounding areas which could be another cause of the higher incidence of APROP in our hospital. The mean GA of our subjects with APROP was 30⁺¹ weeks and the mean birth weight was 1.34 ± 0.32 kg. This trend has also been reported by other authors wherein we see bigger and older babies showing APROP in our country compared to their western counterparts.^[15],[16]

When western standards are applied to our subjects, 25% and 33% of ROP cases would be missed for birth weight and GA criteria, respectively. However, when we apply the current Indian guidelines (Rashtriya Bal Swasthya Karyakram guidelines),^[3] four infants with ROP were outside the birth weight screening criteria of which one infant required treatment. If we consider the GA alone, only one infant with any ROP in our study was more than 34 weeks of GA. In the study done by Dwivedi et al., they reported severe ROP in 10% of infants with GA >34 weeks and 6.5% with birth weight >2000 g.^[8] Patel and Shendurnikar found that 12.4% of their infants with ROP were older than 34 weeks GA.^[17] These trends suggest that the presence of multiple risk factors should be taken into account when considering ROP screening and bigger and older infants with other risk factors should be included.

When risk factors associated with the development of ROP were analyzed, we found a positive association between low GA, presence of blood transfusion, apnea, IVH, anemia, RDS, and presence of two or more risk factors. The associations reached statistical significance for all these risk factors. Septicemia was seen in one-third of infants with ROP, but the association did not reach statistical significance (P = 0.96). Birth weight <2 kg was seen in 80 of the 84 infants with ROP and four of the infants with birth weight >2 kg had ROP, however, the association did not have statistical significance (P = 0.83). This finding can be attributed to the less number of infants in the >2 kg group and also the presence of other confounding risk factors contributing to the development of ROP in heavier babies. Jothi et al. have reported low GA and low birth weight as major risk factors for the development of ROP in their study.^[18] Low birth weight, RDS, and sepsis were found to be strong contributing factors in the development of ROP among mature babies in their study. Patel and Shendurnikar found birth asphyxia, sepsis, multiple blood transfusions, RDS, multiple births, antenatal steroid use, and phototherapy as significant risk factors for ROP in their study.^[17]

None of the infants in our study had Stage IV or Stage V ROP (advanced ROP). About 16.6% of babies in Dwivedi et al.'s study had advanced ROP. In their study, the most important factor for Stage IV and V ROP was a late presentation for screening.^[8] In our study, 188, i.e., 62.25% of infants received their first screening before discharge from NICU. Vinekar et al. have reported that early enrolment of infants for ROP screening in the NICU itself ensured a better enrolment and compliance for follow-up compared to the conventional age of initiating screening.^[19]

Drawbacks of our study include its retrospective nature, lack of oxygen administration details, lack of maternal risk factors, and long-term follow-up. These can be overcome by planning a prospective study with the provision to look into the missing aspects and include a larger number of study subjects.

Conclusion

The rate of ROP noted in our hospital is well within the range reported and published by different centers in the country. A high rate of APROP was observed indicating a need for better NICU practices, judicious use of oxygen, and standard NICU protocols. Low GA, presence of RDS, IVH, anemia, transfusion, apnea, and presence of multiple risk factors were associated with the development of ROP in our hospital. Strict NICU protocols and standard neonatal care may help mitigate the risk factors and help to bring down the rate of ROP.

Acknowledgments

Dr. Anupama S Desai, Professor and Head, Department of Ophthalmology, SDM College of Medical Sciences and Hospital, SDM University, Dharwad, Karnataka, India
Dr. Vijay Kulkarni, Professor and Head, Department of Pediatrics, SDM College of Medical Sciences and Hospital, SDM University, Dharwad, Karnataka, India.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

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