Abstract
purpose. To characterize willingness to pay for private operations and preferred waiting time among patients awaiting cataract surgery in Hong Kong.
methods. This was a cross-sectional survey. Subjects randomly selected from cataract surgical waiting lists in Hong Kong (n = 467) underwent a telephone interview based on a structured, validated questionnaire. Data were collected on private insurance coverage, preferred waiting time, amount willing to pay for surgery, and self-reported visual function and health status.
results. Among 300 subjects completing the interview, 144 (48.2%) were 76 years of age or older, 177 (59%) were women, and mean time waiting for surgery was 17 ± 15 months. Among 220 subjects (73.3%) willing to pay anything for surgery, the mean amount was US$552 ± 443. With adjustment for age, education, and monthly household income, subjects willing to pay anything were less willing to wait 12 months for surgery (OR = 4.34; P = 0.002), more likely to know someone having had cataract surgery (OR = 2.20; P = 0.03), and more likely to use their own savings to pay for the surgery (OR = 2.21; P = 0.04). Subjects considering private cataract surgery, knowing people who have had cataract surgery, using nongovernment sources to pay for surgery, and having lower visual function were willing to pay more.
conclusions. Many patients wait significant periods for cataract surgery in Hong Kong, and are willing to pay substantial amounts for private operations. These results may have implications for other countries with cataract waiting lists.
Cataract is the world’s leading cause of blindness, affecting 18 million people and accounting for 48% of world blindness according to the WHO.
1 In view of the world’s rapidly aging population, the number of affected individuals is projected to reach 40 million by the year 2020.
1 In Hong Kong, a population-based survey has identified cataract as the leading cause of visual impairment, responsible for 28.1% of blindness and low vision.
2
Surgical removal of the lens, the only currently available treatment for cataract-associated vision loss, is capable of restoring visual function in 90% of cases.
3 4 5 6 The willingness of patients to pay for such surgery has been studied as a potential source of income to finance surgical programs in the developing world.
7 8 9 In the developed world, willingness to pay for private-sector surgery
10 has also been examined as a strategy to reduce the length of government waiting lists, in conjunction with strategies such as cataract priority scores.
11 12
In Hong Kong, cataract surgery is available through both the public (Hospital Authority [HA]) and private sectors, with a roughly equal number of cases being performed in each sector. Patients who have their cataract surgery performed in the HA are required to pay a US$13 fee plus the cost of the intraocular lens (IOL), an average of US$200, which can be totally or partially waived if the patient is a recipient of Comprehensive Social Security Assistance or a holder of a medical fee waiver certificate. The current waiting time for cataract surgery in HA hospitals is approximately 35 months
13 ; there is thus much interest in strategies to reduce waiting lists. The HA has recently launched a 2-year program of partial subsidies to encourage patients to undertake cataract surgery in the private sector at a partially subsidized cost of approximately US$1000.
13 Willingness to pay for cataract surgery as a means to reduce waiting time is of relevance not only to Hong Kong, but also to health care systems in Canada and many European countries. As both the United States and China prepare to undertake potentially far-reaching health care reforms, the issue may become of greater importance in these countries as well.
We carried out a questionnaire-based study of patients selected at random from cataract surgical waiting lists at two large public facilities in Hong Kong. Information on patient willingness to pay to avoid the waiting list were collected according to validated techniques.
8 14 The goals of the present study include:
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To obtain data on the mean time spent waiting for cataract surgery.
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To identify the amount of money subjects would be willing to pay for immediate surgery, and to examine various determinants of this amount.
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To obtain information on patients’ reasons for preferring the private or public sector for cataract surgery.
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To determine strategies to reduce time on Hong Kong cataract surgery waiting lists, while maintaining broad access to surgery, that will be most consistent with the data on willingness to pay and attitudes toward public and private sources of care.
This cross-sectional, questionnaire-based telephone interview was conducted between October and December 2007, after pilot-testing of forms and telephone interview procedures on 46 subjects (18 men and 28 women).
To randomly select patients, we used the cataract surgical waiting lists of two large public hospitals which together contained 19,230 patients. Commercial software (Office Excel 2003; Microsoft Inc, Redmond, WA) was used to generate randomized page and row numbers. Patients thus selected were invited to join the study via telephone by a trained interviewer. Oral consent was obtained before initiating the interview. The study was approved by the Joint Chinese University of Hong Kong and the New Territories East Cluster Clinical Research Ethics Committee and was performed in accordance with the World Medical Association’s Declaration of Helsinki.
The following patients were excluded: those who were deaf, had dementia or mental illness, or were otherwise unable to give informed consent or to communicate effectively; those without access to a telephone; those unable to understand Cantonese, Mandarin, or English; and those who had been identified as priority or special needs cases, and were thus subject to reduced waiting time.
A trained interviewer conducted a telephone interview based on a structured questionnaire after pilot testing, as above. Topics included willingness to pay for cataract surgery, self-reported visual function and quality of life,
15 impact of vision on work, general health, and socioeconomic status.
A bidding format
14 16 was used to assess subjects’ willingness to pay (WTP) incrementally larger or smaller amounts for a private-sector surgery according to the following protocol:
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An initial amount was generated at random by computer (Excel; Microsoft, Inc.) and ranged from HKD 1000 (US$128) to HKD 10,000 (US$1282). The interviewer asked the subject if he or she would be willing to pay that amount for cataract surgery in the private sector.
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If the answer was no, the interviewer reduced this amount at US$128 intervals until the subject responded yes. Then, the interviewer increased the amount at US$12.80 intervals until the subject was no longer willing to pay the stated amount.
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If the response to the initial question was yes, the interviewer increased the amount in US$128 steps until the subject responded no. Then, the interviewer decreased the amount at US$12.80 intervals until the subject was willing to pay the stated amount.
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If the subject was not willing to pay US$128, the interviewer reduced the amount at US$12.80 increments until the subject responded yes.
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If the subject was willing to pay more than US$2564, the interviewer asked the maximum amount he or she was willing to pay.
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If the subject responded that he or she was unwilling to pay at all for cataract surgery in the private sector, the WTP figure was recorded as 0.
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At the end of the WTP section of the interview, the interviewer repeated and confirmed the final figure with the subject.
An instrument developed by Fletcher et al.
15 for use in rural Asia and previously validated for use in Chinese
17 was used to assess self-reported visual function. Thirteen questions gathering information on overall vision, visual perception, limitation in daily activities, peripheral vision, near vision, sensory adaptation, light-dark adaptation, visual search, color discrimination, glare disability, and depth perception were each scored from 1 (no problem) through 4 (maximum problems). The total score on the instrument was then rescaled from 100 (the best possible score) to 0 (the worst score).
χ2 tests were used to assess the association between willingness to pay and independent variables including waiting time, attitudes toward cataract surgery and treatment, self-reported visual function, impact of vision on work, general health, and socioeconomic status. For patients who were willing to pay some amount for cataract surgery, ANOVA was performed to assess associations between the amount willing to pay and independent variables enumerated above. Multivariate logistic regression and ANCOVA models controlling for age, educational level, and household income were used to identify potential determinants of willingness to pay and the amount willing to pay.
A total of 607 subjects were selected at random. Four hundred sixty-seven (76.9%) subjects were contacted successfully, whereas 94 (15.5%) subjects could not be reached after three attempts at different times on different days; 46 (7.6%) telephone numbers were invalid. Among those who were contacted successfully, 300 (64.2%) completed all phases of the interview. Of those without full interview data, 105 (22.5%) subjects were ineligible (mostly due to having already had surgery in the fellow eye or difficulty communicating), 55 (11.8%) did not complete the interview, and 7 (1.5%) refused to take part in the study
(Fig. 1) . Among 456 subjects with valid telephone numbers who were eligible for the interview, the overall response rate was 65.8% completing interviews, 67.6% from hospital A and 64.1% from hospital B
(Fig. 1) .
Among participating subjects, 177 (59.0%) respondents were women, about half (48.2%) were 76 years or older, and 142 (47.5%) had no schooling or had completed only preprimary education. Respondents and nonrespondents did not differ significantly with respect to sex, though nonrespondents had been on the waiting list some 4 months longer than the mean for respondents (17.3 ± 15.1 months,
P = 0.03;
Table 1 ). More than half of respondents (55.9%) had monthly household income of less than US$769 compared with the median Hong Kong monthly household income of US$2212 in 2006.
18
Among subjects responding to the question, roughly three fourths (220/294 = 74.8%) were willing to pay anything for cataract surgery. The mean amount willing to pay among such persons was US$552 ± 443
(Table 1) . The maximum acceptable waiting time for nearly half (
n = 131, 43.7%) of respondents was 12 months or less, but about one fifth of respondents were willing to wait more than 3 years for cataract surgery
(Table 1) .
Twenty-eight (9.3%) respondents were considering having cataract surgery in the private sector
(Table 2) . Among them, the purpose of more than 90% was to reduce waiting time. Two hundred seventy-two (90.7%) respondents were not considering having private surgery. For the majority (73.5%), the reason for preferring surgery in the public sector was inability to afford private fees.
Factors potentially affecting willingness to pay for cataract surgery were explored in two separate statistical models. The outcome of the first of these was willingness versus unwillingness to pay something, while the second explored the amount willing to pay among those subjects who would pay something.
In the first model, subjects willing to pay something for cataract surgery were significantly more likely to be willing to wait 12 months or less for surgery than those unwilling to pay anything (
Table 3 ; odds ratio [OR] = 4.34; 95% confidence interval [CI] = 1.75–10.73;
P = 0.002) were more likely to know friends or relatives who had undergone cataract surgery (OR = 2.20; 95% CI = 1.10–4.36;
P = 0.025) and were more likely to use their own savings to pay for the operation (OR = 2.21; 95% CI = 1.05–4.67;
P = 0.038). Age, sex, education level, marital status, family income, time on waiting list, self-reported visual function, impact of vision on work, and hospital site were not significantly associated with willingness to pay
(Table 3) .
In the second model, willingness to pay a larger amount for surgery was associated with considering surgery in the private sector (additional amount willing to pay: US$580 ± 752,
P < 0.0005,
Table 4 ). Subjects who had visual function scores below 80 were willing to pay (US$799 ± 866) significantly more compared with those with scores of 80 or higher (US$607 ± 641,
P < 0.007). Subjects reporting that visual impairment was affecting their work (US$846 ± 642) were willing to pay significantly more than were subjects working without vision problems (US$615 ± 608,
P = 0.04) and subjects who were not working because of vision problems (US$648 ± 833,
P = 0.04). In addition, those who knew friends or relatives who had undergone cataract surgery (additional amount willing to pay: US$133 ± 747,
P = 0.028) or those who use sources other than government benefits to pay for surgery (additional amount willing to pay: US$244 ± 798,
P = 0.043), were willing to pay significantly more. Age, sex, educational level, marital status, time on waiting list, and hospital site were not significantly associated with amount willing to pay. The observed effect of household income did not follow a specific trend
(Table 4) .
Subjects participating in this study had already waited an average of 17 months for cataract surgery. However, only approximately 10% would consider seeking surgery privately, a third were willing to wait at least 2 years, and 40% of subjects at one hospital were willing to wait over 3 years for a public-sector operation. High surgical fees in the private sector are the critical factor that keep the majority of respondents in the public system. The opportunity to reduce waiting time is the principal draw for the relatively small proportion of subjects on the waiting list who consider private-sector operations.
Much evidence suggests that long waiting times for surgery may be deleterious. A recent systematic review found that when waiting times for cataract surgery exceed 6 months, patients may experience a variety of negative outcomes, including vision loss, a reduced quality of life, and an increased risk of falls.
19 Other studies have described an increased prevalence of motor vehicle crashes during protracted cataract surgical waiting times.
20
The mean amount that subjects in this study were willing to pay to reduce surgical waiting time was US$413 (including those who were unwilling to pay anything). This amount is larger than that reported for Manitoba, Canada (US$171), Denmark (US$197) and Barcelona, Spain (US$332).
21 (All amounts have been adjusted for inflation to 2007 US$).
22 In each of these settings, a very small proportion (<2%) of surgery was performed in the private sector at the time of the survey. The average waiting time for cataract surgery in each of the other locations was 3 to 6 months, significantly shorter than in Hong Kong. It seems likely that the longer waits in Hong Kong may account for the greater willingness to pay to reduce waiting time, as the per capita GDP does not differ significantly between the four settings.
22
The median amount of US$413 that subjects on Hong Kong cataract surgical waiting lists are prepared to pay is close to the US$385 median individual monthly income for persons over the age of 65 years in Hong Kong.
23 24 The cost of unsubsidized cataract surgery in the private sector is considerably higher, however—in the range of US$1600 to $2100 and above.
25 Under the government’s proposed scheme, a subsidy of US$1000 will be offered for approximately 7000 cataract surgeries to be performed in the private sector to reduce the waiting list. This figure is more than twice the mean amount that participants in the present study indicated that they were willing to pay.
Besides the desire to reduce waiting time, other factors were also strongly associated with increased willingness to pay for cataract surgery. Patients were significantly more willing to pay something and willing to pay significantly more for surgery if they knew friends or relatives who had undergone surgery. Direct word-of-mouth advertising has been demonstrated to play a significant role in uptake of cataract surgical services in rural China.
26 It appears that the same phenomenon may be present in urban Hong Kong. The source of payment for surgery was also an important factor. Patients who planned to use their own savings were more willing to pay something for surgery. On the other hand, patients who planned to use government benefits were significantly less willing to pay higher amounts for surgery. A report from rural China had similar results
26 : Patients who paid the full fee without their children’s help were twice as likely to undergo cataract surgery in the second eye. Subjects who reported poor vision and that vision was interfering with their work were willing to pay significantly more for operations. This is consistent with previous work showing that a principal determinant of willingness to pay for cataract surgery is the level of perceived need for sight.
27
Our findings have several implications for policy makers. The large majority of patients currently awaiting cataract surgery on the Hong Kong HA lists appear to prefer to stay within the public health system. This suggests that improvements within system, rather than strategies to encourage patients to seek private care, may be more acceptable to health consumers. Our subjects indicate they are willing to pay substantially less than the target figure of US$1000 per case which the government has chosen for its initiative to encourage subsidized private cataract surgeries, which suggests that a lower amount may still stimulate uptake of subsidized private surgery.
An encouraging aspect of our results for the HA system is that patients are willing to pay nearly twice what they are currently charged for public surgery to reduce their waiting time. This finding suggests that strategies to improve the system, such as by providing additional surgeries within the HA, might be paid for through additional modest patient fees. Some patients, such as those who are still working at jobs with high visual demand, appear willing to pay even more for more timely service.
Clearly, it is desirable that access of patients unable to pay such fees not be affected negatively by these strategies. Given the current precedent of waiving all fees for patients on public assistance and of prioritizing patients with worse vision for earlier surgery, it is expected that a modest rise in fees to pay for additional surgeries within the HA system could be implemented in a manner that raises needed revenues but does not restrict access or increase waiting time for poorer patients with pressing visual needs. The need to reduce patient waiting time for cataract surgery in Hong Kong is critical, as a recent population-based study has demonstrated that untreated cataract remains the leading cause of blindness.
2
This study must be understood within the context of its limitations. We drew our sample from only two hospitals, although the 19,230 patients on these two lists represented 38% of the 50,731 patients waiting for surgery on public lists in Hong Kong in 2008.
28 Still, these hospitals may not be fully representative. The education level of our subjects are similar to the general population in Hong Kong, however, their household income was lower,
23 24 as might be expected for older persons who are on the HA waiting list rather than seeking private surgery. The fact that more than 30% of eligible patients could not be contacted, refused participation, or did not complete the interview further raises the possibility of a nonrepresentative sample, although differences we were able to assess between responders and nonresponders appear to be rather modest.
Whereas waiting time for surgery and certain demographic factors were obtained from HA records, data on household income and other potentially sensitive information were drawn entirely from patient interviews. The resulting potential for inaccuracy and bias must be acknowledged. Finally, one of the most important limitations in the present study relates to the methodology used. A potential concern with the willingness-to-pay method is that those surveyed may not truly consider their ability to pay when answering questions. To address this concern, the study adhered to suggested criteria for the administration of reliable willingness-to-pay surveys,
29 including the use of closed-ended questions; clear explanation of both the benefits and costs of the service; and confirming the amount willing to pay at the end of the “bidding” period.
Despite the limitations, this study provides unique data on interaction between willingness to pay and waiting time for cataract surgery in Asia. These findings may not only be relevant to Hong Kong, but also to the growing number of other health care systems that rely on queues to ration eye care.