Utilization of inpatient ophthalmology services in Taiwan—A nationwide population study

The yearly trends in ophthalmic admissions are shown in Fig. 1, which revealed decreasing trend in ophthalmic admissions over time. The number of admissions decreased from 3,248 to 1997 to 2,174 in 2011. Notably, only 2023 admissions were recorded in the year 2003. While Fig. 2 demonstrated change in percentage during these two periods.

A total of 23,696 admissions were recorded for the early period (1997–2005), with a mean of 2,632.9 and a standard deviation of 331.0 admissions per year. By contrast, 13,749 total admissions were recorded for the late period (2006–2011), with a mean of 2291.5 and a standard deviation of 75.3 admissions per year. A significantly reduced frequency of admissions frequency was observed for the late period (p = 0.015) compared with the early period. The mean age of ophthalmic admission patients was 56.3 years, with a standard deviation of 22.2 years during the early period, whereas the mean age was significantly lower for the late period at 55.4 years, with a standard deviation of 20.9 years. The male-to-female ratio was 1.333 to 1 during the early period and 1.285 to 1 during the late period, which represented a significant difference (p < 0.001) that was associated with a reduction in the male predominance associated with admissions during the late period. The mean costs of admission were 956 USD (United States Dollar) during the early period and 1028 USD during the late period, with standard deviations of 589 USD and 635 USD, respectively, indicating a significant increase in costs during the late period (p < 0.001). The mean hospital stay was 4.0 days, with a standard deviation of 4.7 days, for the early period, compared with a mean of 3.6 days, with a standard deviation of 4.0 days, for the late period, indicating a significantly shorter hospital stay during the late period (p < 0.001, Table 1).

We classified diseases codes as operative and non-operative, based on whether the patient received surgery (Table 2).

A total of 34,046 admissions were recorded for operative purposes, with a mean frequency of 2,270 and a standard deviation of 283 admissions each year, compared with 3,399 nonoperative cases, with a mean frequency of 227 and a standard deviation of 42 admissions per year. The mean age was 56.7 years, with a standard deviation of 21.6 years, among patients admitted for operative purposes, compared with the significantly younger mean age of 48.4 years with a standard deviation of 22.1 years observed among patients admitted for non-operative purposes (p < 0.001). The male-to-female ratio of patients undergoing operative treatment was 1.320 to 1, which did not differ significantly from the ratio of 1.266 to 1 for non-operative treatment (p = 0.255). The mean cost of 1039 USD with a standard deviation of 596 USD was significantly higher for patients receiving operative treatment compared with the mean cost of 412 USD with a standard deviation of 393 USD for patients receiving non-operative treatment (p < 0.001). The mean length of hospital stay was 3.7 days, with a standard deviation of 4.3 days, for operative cases, which was significantly shorter than the mean length of hospital stay for non-operative cases of 5.6 days with a standard deviation of 5.6 days (p < 0.001).

Among non-operative cases during the early period, the five most common diagnoses were corneal ulcer (23.71%), eyeball contusion (4.65%), acute angle-closure glaucoma (3.22%), orbital cellulitis (3.13%), and unspecified glaucoma (2.22%; Table 3). The five most common non-operative diagnoses during the late period were corneal ulcer (24.45%), orbital cellulitis (6.09%), optic neuritis (4.00%), vitreous hemorrhage (3.00%), and eyelid abscess (2.73%; Table 3).

The five most common diagnoses for operative cases during the early period were phacoemulsification (19.01%), other extracapsular extraction of the lens (14.42%), other mechanical vitrectomy (10.59%), extracapsular extraction of the lens by simple aspiration technique (6.07%), and other scleral buckling (5.06%), whereas phacoemulsification and aspiration of cataract (25.67%), other mechanical vitrectomy (22.68%), other extracapsular extraction of the lens (6.2%), other scleral buckling (4.43%), and trabeculectomy ab externo (4.27%) were the leading five diagnoses during the late period (Table 4).

During the early period, from 1997 to 2005, cataract surgery was a common reason for operative cases, followed by vitrectomy and scleral buckling. By comparison, during the late period, from 2006 to 2011, cataract surgery remained a primary reason for operative cases, followed by vitrectomy, scleral buckling, and trabeculectomy.

In the studied population, the number of annual admissions ranged from 3,248 to 1997 to 2,174 in 2011. A decreasing trend of the number of annual admissions was noted. The decreasing tend was likely related to the tendency of performing cataract surgery at clinic instead of inpatient department over time.

The number of ophthalmic admissions for the year 2003 was only 2,023. Similar to how the current coronavirus disease 2019 (COVID-19) pandemic has overwhelmed healthcare since 2020, in 2003, the SARS epidemic occurred in Taiwan. The pandemic impacted clinical management, which was reflected in the changes in ophthalmology admission services, many of which are considered elective procedures.

The annual ophthalmic admission rate of Taiwan was reported as 108–162 per 100,000 population, which was higher than that of 16 per 100,000 population in the United States [1]. The mean cost of ophthalmic admissions was approximately 1,000 USD in Taiwan, which was one-ninth the average cost of 9,700 USD in the United States [1]. The mean age for the ophthalmic patients admitted in Taiwan was approximately 56 years, which was much older than the mean age of 44 years reported for the United States [1]. This discrepancy may be due to the fact that cataract surgery still represented a significant proportion of ophthalmic admissions in Taiwan while the same operation was mainly provided under an outpatient setting in the United States.

The male-to-female ratios revealed a male predominance in both countries, with men representing approximately 56.5% of admissions in Taiwan compared to that of 51.6% in the United States [1]. Another study from Nigeria also demonstrated a similar male-to-female ratio of 1.30 to 1 [2]. The mean hospital stays associated with Taiwanese ophthalmic admissions were slightly longer than that of the United States. Patients spend an average of 3.7 days for operative and 5.6 days for non-operative diagnoses in hospital, compared to that of 3.2 days for both types of cases in the United States [1]. The average hospital stay in Nigeria was even shorter, at 2.86 days [2]. The length of the hospital stay in Germany was similar to that reported for Taiwan. As for the trend of Similar to Germany⁶, the hospital stay showed a declining trend from 3.9 to 3.4 days.

Admissions for operative diagnoses outnumbered that of non-operative diagnoses, at a ratio of 10 to 1, indicating that ophthalmic admissions were primarily utilized for surgical purposes. The most common underlying reasons for ophthalmic admission in our study included cataract surgery during both the early (39.50%) and late periods (31.89%), followed by vitrectomy (10.59% in the early period and 22.68% in the late period), scleral buckling (5.06% in the early period and 4.43% in the late period), and trabeculectomy (4.27%), which emerged during the late period. Cataract surgery played a pivotal role in ophthalmic admissions but demonstrated a declining trend, similar to the study performed in Germany [3]. By contrast, vitrectomy showed an upward trend in ophthalmic admissions, similar to the studies performed in the United States [1] and Germany [3], whereas scleral buckling revealed a downward trend, which might be due to advancements in vitrectomy technology. Due to an aging population and the complexity of glaucoma surgery, trabeculectomy began to emerge as a common procedure during the late period. In Nigeria [2] and Thailand [4], the primary reasons for inpatient ophthalmic services were cataract and glaucoma surgeries, which reflect an aging population and were similar to the Taiwanese ophthalmic admission landscape observed in this study. The study from Thailand also showed that the five most common inpatient eye diseases, based on ICD-10-CM codes, were disorders of the lens; conjunctivitis; disorders of the sclera, cornea, iris, and ciliary body; disorders of the choroid and retina; and glaucoma [4].

As Table 5 showed Taiwan’s inpatient admission utilizations might be an epitome for the admitted disease landscape overtime globally, which demonstrated decreasing cataract surgery performed as inpatient services and increased vitreoretinal surgery as well as trabeculectomy of glaucoma patients, and also the downward trending of the hosptial stay and uprising costs worldwide.

Among non-operative diagnoses, corneal ulcers (from 23.71 to 24.45%) were the most common during both the early and late periods, followed by contusions of the eyeball (4.65% in the early period), orbital cellulitis (3.13%), acute angle-close glaucoma (3.22%), and unspecified glaucoma (2.22%) during the early period; whereas orbital cellulitis (6.09%), optic neuritis (4.0%), vitreous hemorrhage (3.0%), and abscess of the eyelids (2.73%) were more common during the late period. Corneal ulcer has remained the leading cause of admissions for both the early and late periods, accounting for almost a quarter of non-operative ophthalmic admissions. However, an upward trend in other infections, such as orbital cellulitis (from 3.13 to 6.09%) and lid abscesses (2.22%), emerged during the late period. Similarly, the most common diagnosis for ophthalmic admissions was orbital cellulitis, followed by orbital fracture and lid abscesses in the United States [1]. The emergence of methicillin-resistant Staphylococcus aureus [8] during the last decade in both Taiwan and the United States has been associated with the increased incidence of orbital and lid infections. In another study performed at a Nigerian tertiary hospital [2], the primary non-operative cause for ophthalmic admission was ocular trauma, which accounted for 14.3% of ophthalmic admission; although the prevalence of ocular trauma in our study was only 4.65%, this propensity was reflected during the early period. Another common reason for non-operative admissions during the early period was glaucoma, especially angle-closure glaucoma; however, this diagnosis was more common during the early period. The reasons for this shift might be due to the high prevalence of primary angle-closure glaucoma (PACG) among people from Asia, especially those from Taiwan, and the laser treatment that has been developed for PACG prevention can be performed as an outpatient eye care service, which may have decreased ophthalmic admissions for PACG.

The most distinct feature in our study was that corneal ulcers were the top diagnoses in our present study for both the early and late periods. In Taiwan, access to contact lenses is available without an ophthalmologist’s prescription, despite regulations that aim to require ophthalmologist recommendations. Unfortunately, corneal ulcers can develop due to poor education regarding the appropriate use and hygiene of contact lenses for the users. Keratitis accounted for roughly one million outpatient and emergency eye care visits in the United States [9]. Keratitis is known to be a potential precursor of corneal ulcers. Corneal ulcers frequently occur among contact lens wearers, especially those who use extended contact lenses. One study, performed as a retrospective chart review, revealed that corneal ulcers were the most prevalent among young women aged 25 to 34 years (with an incidence rate of 60.3 per 100,000 person-years) [10]. Corneal ulcers can lead to poor clinical outcomes, such as corneal scarring or blindness; therefore, our results raise concerns regarding the appropriate use of prescriptions of contact lenses in Taiwan, which might necessitate additional regulations. Another factor contributing to the high rate of corneal ulcers might be the relatively high prevalence of myopia [11] and the relevant orthokeratology of rigid, gas-permeable, extended-wear contact lenses for myopia control that are used by the grade school and high school student populations in Taiwan.

The mean ages of operative and non-operative patients were 56 and 48 years, respectively, indicating that non-operative patients were much younger than operative patients. Operative patients were primarily treated for cataracts and vitreoretinal or glaucoma surgeries, which are diagnoses primarily associated with aging; by contrast, the non-operative patients were primarily treated for infection, trauma, and inflammation (corneal ulcer, orbital cellulitis, and blunt eye injuries), which are diagnoses associated with younger demographics [10].