Reasons for patient defaults from diabetic retinopathy screening in general outpatient clinics (GOPCs) in Hong Kong - A cross sectional study

Cho-ting Shiu 邵楚婷, Pang-fai Chan 陳鵬飛, Loretta KP Lai 黎潔萍, Matthew MH Luk 陸文熹, David VK Chao 周偉強

HK Pract 2019;41:3-10

Summary

Objective:
(1) To investigate the relationship between patients’ personal characteristics and non-attendance among patients who had scheduled appointments for diabetic retinopathy screening in two of the General Outpatient Clinics (GOPCs) of Kowloon East Cluster (KEC) of Hospital Authority (HA) in Hong Kong.
(2) To investigate the reasons for non-attendance.
(3) To suggest changes that can improve the non-attendance.
Design: A cross-sectional study
Subjects: Those with type II diabetes and booked diabetic retinopathy screening sessions from 1^st January 2013 to 31^st December 2013.
Main Outcome measures:
(1) Factors associated with non-attendance.
(2) Reasons for non-attendance.
Results: (280 (70%) out of 400 subjects were recognised as attenders. The remaining 120 (30%) subjects were considered as non-attenders. By unconditional logistic regression adjusting for confounding factors, male gender, high HbA1c and diabetic retinopathy were significantly associated with non-attendance. The main reported reason of non-attendance was that patients forgot the appointment (59.2%).
Conclusion: Measures such as telephone reminders and patients’ empowerment may be needed to reduce non-attendance in diabetic retinopathy screening.

Keywords: Diabetic retinopathy, screening, non-attendance, default, General Outpatient Clinics

摘要

目的：以香港醫院管理局九龍東聯網轄下兩所普通科門診已預約糖尿病視網膜病變篩查的病人為對象。
（1）研究病人特性和缺席的關係
（2）研究缺席的原因
（3）提供建議以改善缺席情況。
設計：橫切面研究。
研究對象：2013年1月1日至2013年12月31日期間，已預約糖尿病視網膜病變篩查的第二型糖尿病人。
主要測量內容：
（1）缺席的相關因素。
（2）缺席的原因。
結果：400位對象中，280位（70%）為應約者，其餘280位（30%）為缺席者。以邏輯迴歸法調整干擾因子後，男性、高糖化血色素值和糖尿病視網膜病變都與缺席有顯著的關係。忘記預約日期是缺席的主要原因。（59.2%）
結論：可採取電話提示和鼓勵病人自主來減少糖尿病視網膜病變篩查的缺席情況。

關鍵字：糖尿病視網膜病變、篩查、缺席、不履行、普通科門診。

Introduction

Diabetic retinopathy is one of the leading causes of blindness worldwide.¹ It can be categorised into nonproliferative retinopathy and proliferative retinopathy. Based on the clinical characteristics, it can be further classified into mild, moderate and severe stages.²

According to the Center for Diseases Control and Prevention (CDC) of United States, 28.5% of people with diabetes aged 40 years or older had diabetic retinopathy while 4.4% of them had severe vision loss due to advance diabetic retinopathy.³

Diabetic retinopathy screening aims at early identification of eye complications among diabetic patients. The American Optometric Association (AOA), therefore, recommended diabetic patients to have regular diabetic retinopathy screening to prevent vision loss.⁴ In the United States, only about 53.4% of diabetic patients aged 18 years or older have ever had diabetic retinopathy screening in the past years and therefore, the government’s Healthy People 2020 programme aims to increase the rate of diabetic retinopathy screening to 58.7% by 2020.⁵

In Hong Kong, Risk Assessment and Management Programme - Diabetes Mellitus (RAMP-DM) was commenced in 2010 in GOPCs. It aims at providing diabetic complication assessment including diabetic retinopathy and improving the quality of care of diabetes patients. Patients with newly diagnosed diabetes mellitus (DM) were referred by GOPC doctors to RAMP-DM complications assessment. The retinopathy assessment appointments were usually arranged within 3 to 6 months. The subsequent follow-up appointment interval would be determined according to the risk of developing severe retinopathy taking into consideration the latest HbA1c level, DM duration, latest blood pressure and severity of diabetic retinopathy. The subsequent follow-up appointment interval ranged from 6 months to 2 years.

A structured diabetic retinopathy screening programme is of vital importance in the management of diabetes patients. However, non-attendance is a major problem of these programmes which hinder proper clinical care to be delivered to patients.

Studies showed that general non-attendance rate of medical appointments were different among different countries, which varied from 6.5% to 19%.^6-9 Some characteristics for non-attenders with diabetes who dropped out from diabetic care were studied in different countries such as Malaysia, Japan and United Kingdom (UK), etc.. Young age and male were identified as features that related to high non-attendance rate in diabetic retinopathy screening.^7,9-12

Some studies showed that non-attenders were more likely to have no medication for diabetic mellitus, low plasma glucose and HbA1c levels and longer duration of diabetes.^8-9,13 This suggested that patients with relatively good control on diabetes were more likely not to attend diabetic care. On the other hand, a study in the UK showed that patients who had poor HbA1c control were likely to miss the appointment of diabetic retinopathy screening.¹⁴

Forgetting the appointment was a major reason for non-attendance which agreed well in many studies.^7,15-16 Patients would either forget the appointment date if it was arranged a long time ago, or forget to cancel the appointment even though they knew they were not able to attend well in advance. The longer the patients had to wait for the appointment, the more likely that they would not show up.¹⁷ Some studies found that it was related to administration, either mistakes from the appointment system or communication errors between staff and the patients.^16-17

Other reasons for non-attendance included not feeling well, having work commitment, being transferred to another eye care service and limited personal mobility.^7,18 Some patients thought that they had no problems with their eyes and few were afraid of mydriatic effect that would prohibit driving.^19-20 Studies showed that the non-attendance rate for diabetic retinopathy screening was about 16.7% in Malaysia and 19% in United Kingdom.^7,9

High non-attendance of diabetic retinopathy screening could have serious impact on patients’ quality of life and, as a result, increase the medical cost for caring of them due to loss of productivity.²¹ Moreover, non-attendance leads to an increase in waiting time and therefore lengthens the queue for a screening appointment which causes wastage in manpower and resources.¹⁰ Therefore, identifying the characteristics and the underlying reasons for non-attenders is essential.

The objective of this study is to investigate the associated factors and reasons of non-attendance in diabetic retinopathy screening in GOPCs and to suggest changes that can improve the attendance rate.

Methods

This is a cross sectional study and is approved by the Hospital Authority Research Ethics Committee (Kowloon Central Cluster / Kowloon East Cluster) and the Chinese University of Hong Kong Survey and Behavioural Research Ethics Committee. A total of 400 diabetes patients, who had booked an appointment for diabetic retinopathy screening from 1^st January 2013 to 31^st December 2013 in two GOPCs in KEC of Hospital Authority, were subjects of this study. The chosen GOPCs were located in a local district with implementation of RAMP-DM. All diabetes patients followed up in the GOPCs were having type II diabetes mellitus.

Attenders were defined as all subjects who had attended the diabetic retinopathy screening appointments from 1^st January 2013 to 31^st December 2013. Non-attenders were defined as subjects who did not attend any scheduled diabetic retinopathy screening appointments from 1^st January 2013 to 31^st December 2013 and attended the clinic again from 1^st March 2014 to 30^th April 2014 for diabetic retinopathy screening. Subjects aged over 18 were included in this study while subjects who refused to take part in the study, could not communicate in Chinese or English, were mentally deprived and were unable to give consent were excluded. The researcher obtained the list of potential subjects who fulfilled the inclusion criteria from the Clinical Data Analysis and Reporting System (CDARS) database. There were a total of 11891 diabetic retinopathy screening appointments booked from 1^st January 2013 to 31^st December 2013 in the two participating clinics. The sampling method in this study was simple random sampling. Every potential subject was assigned with a number. A total of 400 subjects were chosen randomly.

Between 1^st January 2013 and 31^st December 2013, there were 16,150 patients attended for diabetic retinopathy screening and 6,774 patients did not attend for diabetic retinopathy screening. The non-attendance rate was about 30 per cent. Based on the rule of thumb of calculating the sample size of multiple logistic regressions²², number of observations of smaller outcome group should be more than 10 times number of predictors. In the database, the non-attendance rate was about 30%.

There were 8 independent variables in the study. Since the educational level (no formal education, primary, secondary and tertiary) and presence of diabetic retinopathy (No retinopathy, non-sight retinopathy, sight retinopathy and not known) were sub-divided as 4 categories, there were 12 independent variables required to fit in the logistic regression model. The sample size would be 10*12/30%=400.

In this study, the sample size was set as 400. Number of defaulters (cases) was 120 while number of attenders (controls) was 280, which were selected by simple randomization from the generated patient list. Unmatched case control study was used as age, gender and other personal features were possible covariates and explanatory factors.

The researcher generated the list of potential subjects who fulfilled the inclusion criteria from the Hospital Authority Clinical Data Analysis and Reporting System (CDARS) database. The sampling method in this study was simple random sampling. Every potential subject was assigned with a number. Those with 20^th multiples were chosen as subjects. Total 400 subjects were chosen in this way.

Patient characteristics including age, gender, educational level and clinical parameters including duration of diabetes, glycated haemoglobin (HbA1c) level, use of anti-diabetic medication, presence of diabetic retinopathy and length of appointment interval of both non-attenders and attenders group were collected from HA Clinical Management System by the researcher.

A questionnaire was developed based on previous literatures review on investigating the reasons for non-attendance. Only non-attenders were invited to fill in the questionnaires. Considering the feasibility for the study participation, they were invited to fill in the questionnaires when they were returning for diabetic retinopathy screening from 1^st March 2014 to 30^th April 2014.

Informed written consent was obtained. Subjects who agreed to participate in the study were asked to choose one or more reasons for non-attendance from the list and returned the questionnaire on the same day. For illiterate subjects, the researchers would interview the subjects and help them to fill in the questionnaires. (See Appendix I)

In this study, the predictor variables were the demographic data including age, gender and educational level and clinical parameters including duration of diabetes, HbA1c level, use of anti-diabetic medication, presence of diabetic retinopathy and appointment interval. Reasons of non-attendance were also collected through questionnaires.

All of the data was analysed using Statistical Package for Social Sciences (SPSS) software version 21. Age, DM duration, Hba1c level and the appointment interval were continuous variables and univariate analysis between attenders and non-attenders were calculated by paired t-test with significance set at p<0.05 and confidence interval 95%. Gender, educational level, severity of diabetic retinopathy and the use of DM medication were categorical variables and univariate analysis between attenders and non-attenders were calculated by Chi square test with significance set at p<0.05 and confidence interval 95%.

Multivariate analysis was done by unconditional logistic regression to adjust for confounding factors and to test for the association between the likelihood of non-attendance and demographic data and clinical parameters. Mode was used to assess the reason for non-attendance given by the non-attenders.

P values for all end points were two-sided. P values of less than 0.05 were considered to be statistically significant.

Results

The demographic and clinical features of the subjects are shown in Table 1. In the study period, 280 (70%) subjects of 400 were recognised as attenders. The remaining 120 (30%) subjects were considered as non-attenders.

Table 1 showed that gender, Hba1c level, appointment intervals and severity of diabetic retinopathy were significantly associated with patients’ non-attendance. Males were significantly associated with non-attenders (p=0.016). 65 subjects (54.2%) of the 120 non-attenders were male in contrast to 115 subjects (41.1%) of the 280 attenders were male.

HbA1c levels of non-attenders were significantly greater than that of the attenders (p=0.002). Also, the appointment interval was significantly shorter for non-attenders than the attenders (p=0.000). Diabetic retinopathy severity was also significantly associated with non-attendance (p=0.004).

All the variable factors were analysed with logistic regression model which showed the likelihood of non-attendance was independently associated with gender, HbA1c level and presence of diabetic retinopathy. The odds ratio shown in Table 2 was adjusted for age and confounding factors such as gender, etc. Females were more likely to attend the appointment than males (OR 0.613, 95% CI: 0.384-0.978). Also, subjects with higher HbA1c level were (OR 1.217, 95% CI: 1.015-1.460) more likely not to attend the appointment than subjects with lower HbA1c level (%). Subjects with diabetic retinopathy were (OR 1.607, 95% CI: 1.001-2.580) more likely to default the appointment than those with no retinopathy. Age, use of anti-diabetic medication, duration of diabetes, appointment interval and educational level were not associated with non-attendance. However, the association between lengths of appointment intervals with non-attendance disappeared after analyzing by logistic regression. HbA1c and severity of diabetic retinopathy confounded the association between lengths of appointment and non-attendance.

Neither age, use of DM treatment, DM duration, lengths of appointment intervals nor education level were associated with non-attendance.

As shown in Chart 1, the reasons for non-attendance were related to forgotten the appointment (82%), not in Hong Kong (5%), work commitment (5%), felt unwell (2%) and follow-up in eye (1%). The main reason for non-attendance was forgetting the appointment.

Discussion

Our findings suggested that male gender was an independent predictor for non-attendance. It was consistent with other international studies.⁷ Behaviour of male patients who tend to avoid help or delay help from others in healthcare may explain this finding.⁸

In this study, subjects with higher HbA1c level are more likely not to attend an appointment than those with lower HbA1c level which was consistent with a UK study.¹⁴ This finding suggested that diabetic patients with poorer control tend not to attend the diabetic screening. Diabetic patients with existing diabetic retinopathy were also more likely not to attend the screening appointment in our study which was consistent with a Japanese study.⁹ As HbA1c level has an important impact on the microvascular complications such as diabetic retinopathy, non-attenders with poorer HbA1c level are more likely to develop diabetic retinopathy.²³

The main reason for non-attendance in this study was that patients forgot the appointment date which was consistent with other studies.^7,15-16 Different reminder tools including letters, telephones, and emails are suggested to reduce the tendency for patients missing the appointments.^24-25 However, a study showed that most patients preferred telephone reminders than other reminder tools.⁷ Telephone reminder is a very cost effective way to remind patients especially for those who have high probability not to attend the appointments, as we found in this study that the commonest cause for default was because they forgot the appointment.¹⁷

A study that used randomised control trials to identify healthcare interventions in clinical setting found that telephone prompts could positively reduce non-attendance.²⁶ Another review study also suggested that a telephone prompt should be delivered 24 hours before the appointment to arouse patients to attend.²⁷ A telephone prompt delivered to patients on the day before the appointment might be able to reduce non-attendance in diabetic retinopathy screening. Further studies are necessary to identify its effectiveness. Other strategies that might help to improve the non-attendance include “orientation statement”^30,31 and sending an information pack to the patients before the appointment.³² In this era of smartphones, development of appointment Apps could be explored also. In the meantime, a reminder SMS message may also serve the purpose. Further studies are necessary to identify their effectiveness.

Male non-attenders with poorly controlled DM more likely belonged to the group of patients with lower motivation in diabetes self-care, patient empowerment might also be useful in improving their attendance.

Limitations

There were a few limitations in this study. Firstly, only those re-attended patients could be recruited as subjects. Lost to follow-up patients could not be recruited. Also, there might be recall bias in this study. As the structured questionnaire required subjects to recall their reason for non-attendance, some subjects might have poor memory and were not able to recall all of the true reasons. Thirdly, as the research was conducted in two chosen GOPCs in the same district, the result might not be generalised to other GOPCs in Hong Kong.

Conclusion

Non-attendance of diabetic retinopathy screening was mainly due to patients forgetting the appointments. As most of them were appointment related, telephone reminders may be useful to tackle this problem. In the future, further studies are necessary to develop the possible ways to reduce non-attendance in diabetic retinopathy screening. Intervention studies are necessary to examine whether telephone reminders, SMS message reminders, appointment Apps or enhancing communication strategies could have a significant improvement of non-attendance in diabetic retinopathy screening especially in the following groups of people including males, those with high HbA1c level and existing diabetic retinopathy.

Acknowledgments

We would also like to thank our Department optometrists, Ms. Wong On Ying and Ms. Wong See Wan, for their help in data collection.