Health economics and manual small-incision cataract surgery: An illustrative mini review : Indian Journal of Ophthalmology

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Health economics and manual small-incision cataract surgery: An illustrative mini review

Bali, Jatinder; Bali, Ojasvini1; Sahu, Amulya2; Boramani, Jagannath3,4; Deori, Nilutparna5

Author Information
doi: 10.4103/ijo.IJO_1266_22
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Abstract

Cataract is a major cause of preventable global blindness. After uncorrected refractive error, it is the second cause of moderate or severe visual impairment (MSVI <6/18).[1] It is treated by extracapsular cataract extraction intraocular lens (ECCE-IOL), phacoemulsification (PE), manual small-incision cataract surgery (MSICS), and femto laser-assisted cataract surgery (FLACS) among other procedures. Approximately 17.7 million phacoemulsification procedures were performed in 2018, and the Cataract Surgery Devices Market expected to grow with a CAGR of 4.2% from 2022 to 2027.[2] Perioperative complications can affect 4.2%–8.6% of all surgeries performed and may be associated with a worse postoperative visual outcome.[34] Most studies have studied the clinical outcomes of MSICS and compared it with other techniques. Economic evaluation is a comparative analysis of costs and outcomes of different alternatives. Drummond et al.[5] described six categories of economic evaluation: outcome description, cost description, cost-outcome description, efficacy or effectiveness analysis, cost analysis, and full economic evaluation as shown in Fig. 1. The latter three can be used to compare different techniques or alternatives.

F1
Figure 1:
Six categories of economic evaluation

Full economic evaluation measures both costs and outcomes of compared alternatives. The cost is measured in monetary units while the outcome component measurement can vary. On the basis of outcome measurements, the full economic evaluation can be of the following types as shown in Table 1: cost–benefit analysis (CBA), cost-minimization analysis (CMA), cost-effectiveness analysis (CEA), cost–consequence analysis (CCA), and cost–utility analysis (CUA).[5] The National Institute for Health and Clinical Excellence (NICE) had recommended CEA and CUA over others due to technique limitations in CBA and CMA since clinical effectiveness measurement is usual in healthcare.[6]

T1
Table 1:
Full Economic Evaluation Techniques in Healthcare

The recent femtosecond laser-assisted versus phacoemulsification cataract surgery (FEMCAT) by Schweitzer et al.,[7] which was a multicenter masked randomized superiority and cost-effectiveness, trial has sharply shifted the focus on to the commercial and health economics aspects of the methods of cataract extraction. Very few studies are available on the costing and economic aspects of MSICS and the need to map out the known and unknown areas therefore arises for this method.

We decided to study economic evaluation measures like cost effectiveness, cost utility, and cost parameters in cataract patients who underwent cataract extraction by MSICS in comparison to the gold standard phacoemulsification in randomized controlled trials and observational real-world data in publications in indexed journals.

This systematic review compared MSICS and phacoemulsification. Ethics Board Approval was not required because secondary data was used which consisted of reviewing published manuscripts which had Institution Ethics Board Approvals. Heterogenous data sources including NHS Economic Evaluation Database, Health Technology Assessment Database, Scopus, Embase, Medline, PubMed and Cochrane databases were searched using the keywords mentioned in supplementary materials.

Duplicate entries were removed electronically. If English translations were available, then non-English studies were included, but no contact with any author was made for this purpose or otherwise. Two hundred twenty-six studies were screened manually and 32 studies were found to be eligible for inclusion in the review. The decision to carry out detailed meta-analysis was left to availability of adequate high-class evidence to draw useful conclusions failing which a narrative review was to be performed. Hand searching of articles from reference lists of obtained articles was also done by OB. Data was sought on cost, incremental cost, effectiveness, utility, and incremental cost-effectiveness ratio (ICER) along with any surrogate descriptors or markers used in full economic analysis. Two assessors JB and OB after doing a pilot validation on 5 studies to check consistency of assessment made the bias tables. The consensus decision was valid. In case of a stalemate or tie, the tiebreaker was adjudicated by AS who was blinded to the selection of JB and OB. Only reasons, if any were given, from assessments of raters were provided to AS for adjudication of tie break. The list of citations included is given in the supplementary material.

Heterogeneity was assessed by calculating I2 for quantifying inconsistency if the study designs were similar:

In this equation, Q is the χ2 statistic and df is its degrees of freedom. Thresholds for the interpretation of the I2 statistic were specified as follows: 0% to 35% as not important; 35% to 60% as moderate heterogeneity; 60% to 90% as substantial heterogeneity; 75% to 100% as considerable heterogeneity. Since heterogeneity depends on many factors, the latter two would depend on other value judgments also. In case of substantial or considerable heterogeneity, the authors would not be calculating summary forest plot. Standardized mean difference (SMD) with 95% CI for continuous variables like cost, ICER, etc., was to be employed if the studies were comparable in design after statistical heterogeneity evaluation by I2 statistic. A randomeffects metaanalysis by DerSimonian–Laird method was to be employed if the samples were large. However, the literature showed a paucity of comparable data on MSICS.[8]

Results

A total of 226 studies were screened and 32 were selected as shown in Table 2.

T2
Table 2:
Flow diagram of review

Discussion

The Cochrane systematic review demonstrated that MSICS gave better uncorrected visual acuity and less surgically induced astigmatism compared to ECCE, but the quality of evidence was low.[9] Similarly, comparing phacoemulsification with MSICS the review found that there were no differences in terms of visual outcome between these two interventions at 6 and 12 months follow-up, but information on vision-related quality of life and cost utility was not easily available.[10]

Costs of cataract surgery are divided into fixed costs and overheads or variable costs. The fixed costs are those spent on buildings (sunk costs) and machines, etc., (capital expenditure). These remain unchanged over medium term and are clubbed under capital (C) costs in analysis. The variable costs are called overheads or can be divided into labor (L) and material (M) costs. Labor costs include salary, welfare, medical fee, training fee, and other fees for all workers working directly in the facility. The average labor cost/case uses the expenditure on OPD, IPD, OT, ophthalmologists, and supporting healthcare personnel.[11] Material costs are the costs of materials and public utilities expended in the OPD, ward, operation theater including medical supplies used, medicine for cataract patients after surgery, etc. The calculation of material costs is limited to those expended directly on these cataract cases. If hospitalization is used, then the costs are added to the material costs.[11]

Experience of Ruit et al., Muralikrishnan et al., and Gogate et al. shows that use of locally manufactured IOLs, viscoelastics, and pharmaceuticals dramatically lowered the costs as the locally made PMMA lenses could be as low as $1.44.[12–15] The foldable lenses manufactured in India are also now available at a fraction of the cost with some IOLs costing one-tenth of the price of those imported from the United States.[15] Gogate et al. in their single-masked randomized controlled clinical trial with four surgeons conducting a total of 200 surgeries each of phacoemulsification and MSICS reported that PE costing US $69.40 was more expensive than MSICS at US $38.95.[12] The surgeons reused some consumables and brought the costs for PE down to US $42 while MSICS costed US $15. Fixed facility costs in this study included the phacoemulsification machine. They were added to the costs of consumables and the cost of the procedure as calculated taking the average of the expenditure. The fixed facility cost was $10, and the resultant cost therefore was about $49.40 for PE and $28.95 for MSICS. With reuse of some consumables, the adjusted cost difference was $32 for PE to $5 for MSICS as seen in Table 3.[13] Malik et al.[16] reported that the cost of rigid PMMA IOL implants with MSICS lenses was cheaper than PE with rigid PMMA lenses as well as phaco with foldable lenses. The major limitation of this study was the costing procedure not being similar to other studies. Thus, only the trends can be used.

T3
Table 3:
Cost Analysis in Cataract Extraction

Hennig et al.[17] from Lahan, Nepal, in their large 8955 patient study reported that PE was more expensive than MSICS. The consumables cost was US $4.28 per operation for PE. The cost of the rigid IOL for 8410 patients was $1.94 while it was US $16.50 for 545 patients receiving foldable IOL. The cost of consumables per cataract operation including IOL, all medicines used before, during and after surgery, anesthesia, viscoelastics, irrigation solution, disinfectants, and eye pads was approximately US $6.50 at 2001 rates. The high import content shifted the cost of surgery by PE upwards. In developing countries, the locally made IOLs have been available for less than three pounds (GBP) while the lens in the western world was priced at about ≤38.00 (GBP).[18] Minassian et al.[18] had reported that the cost of PE surgery was less costly compared to conventional methods in Europe but he failed to take the capital cost of the PE machine into account. Muralikrishna et al.[14] used a “micro-costing approach” to report on the three procedures: PE, MSICS and ECCE-IOL. The patient’s direct and indirect costs for each procedure were calculated by interviewing staff and patients. They used assumptions about prices for relevant cost items such as transportation, food, medicine, spectacles, and economic productivity loss. Averaged out costs showed that provider’s direct costs were highest for PE (US $25.55), followed by MSICS ($17.03) and ECCE-IOL ($16.25). Average direct and indirect patient costs were highest for ECCE-IOL ($19.85), while the costs for PE and MSICS were identical ($12.37). ECCE-IOL had the highest total costs and MSICS had the lowest total costs from the societal perspective, with PE occupying the intermediate position. Each procedure is suitable for certain situations and the procedures per se cannot be compared from the operational viewpoint in that situation.

The capital costs need to be amortized over the lifecycle of the product machines, the annual maintenance costs for devices, depreciation cost for the medical devices, and the buildings. Such investments can vary temporally, and price factor correction as well as purchasing power parity are desirable but not possible. The capital investment on the PE machine was ≤35,000 in 1992 according to Rosenthal et al. which had risen to US $70,000 for AMO Whitestar used by Ruit et al. in their 2007 study.[1519] The difference in instrumentation in Ruit’s case can be gauged from high-end operating microscope at US $52,000 for PE to Zeiss 1 FR operating microscope at US $9,200 for MSICS.[15] It is not possible for real-world data to differentiate the microscopes and instruments because after installation they are used as a continuum between different surgeons.

Surrogate costing measures like the billing cost by the private secondary-care provider with direct patient and insurance payouts can be used as billed-in cost with the assumption that sustainable costs have been levied. However, a bias creeps in as there is no scope of judging the upward marking of prices to include reasonable return on investment and if included then the quantum of discounted net present value of such returns.[112021] Therefore, secondary data based studies were placed separately and heterogeneity of studies obviates the use of a narrative review. The societal costs for PE include the requirement for a stable electric power supply and centers which can absorb the costs of the machine and its annual maintenance costs. MSICS, on the other hand, was found to be feasible in smaller cost setups with even a small generator providing the power. The disposables and consumables, though similar, include things like PE needles (some manufacturers) tubing, cassettes, etc., for the phacoemulsification machine.[111314172021]

Brown et al. and Lansingh et al. determined the utility for cataract surgery of the better seeing eye using HRQoL.[2223] They reported that utility y = −0.04792x3 + 0.191x2 − 0.4233x + 0.9128 where x = Visual Acuity in Log MAR units. This utility analysis can be modified for the worse eye by using a weighting factor of 0.3, as reported by Scanlon et al.[24] Khan A et al.[25] reported that there were no significant difference in effectiveness between PE and MSICS on utility parameters as shown in Table 4.

T4
Table 4:
Utility Difference Between Phacoemulsification and MSICS[25]

However, the cost utility scores for these parameters showed significant differences between PE and MSICS. The cost-utility difference was significantly better for MSICS compared to PE as shown in Table 5. Thus the two comparison measures, utility and cost-utility ratio, need to be differentiated from each other as illustrated in the two tables.

T5
Table 5:
Cost-Utility Ratio Difference Between Phacoemulsification and MSICS

Cost-effectiveness and cost utilization analysis are important tools for decision-making for healthcare providers and policymakers. Incremental cost effectiveness ratio (ICER) is a popular measure of cost-effectiveness or marginal utility of the approaches under study. ICER is a measure of the additional cost incurred when choosing the less effective intervention against the more effective one to achieve 1 unit of effectiveness. It is measured as

A = Current Gold Standard

B = The intervention under study

Effectiveness in cataract surgery can be visual acuity, quality of life, complications, and astigmatism beyond a particular level. For the purpose of this review, we focused on the visual acuity and complications. If there is a significant difference between alternatives then the cost minimization approach will fail. The difference in effectiveness needs to be adjusted using suitable equalization methods and approaches like quality of life, disability-adjusted life years (DALYs), and quality-adjusted life years (QALYa) become important. Broadly, DALY measures health loss in the quality of life while QALY measures the same quality of life in health gain. Using a purchasing power parity principle for the country the per capita gross national product can be used for standardization. The quality-adjusted life year (QALY) is an outcome measure that expresses the duration and quality of life. It is the main pillar of cost-effectiveness analyses. Early rehabilitation favours better QALY values and decision makers have frequently used the World Health Organization (WHO) benchmark based upon a country’s gross domestic product (GDP) per capita with services exceeding three times GDP per capita being considered economically unattractive.[26] There was no statistically significant difference in VA gain or complication rate between MSICS and phacoemulsification in most studies.[11–15]

Traditionally lower astigmatism and faster recovery in favour of phacoemulsification as compared to manual small-incision cataract surgery has been reported by many authors. The difference, however, was not carried forward at three-month meta-analysis.[21] A mild myopic error induced by incision modification in MSICS can enable spectacle independence in resource constrained environments.

According to the study by Jongsareejit et al.,[11] there were no differences in the outcomes of visual acuity, astigmatism, and complications between phacoemulsification and MSICS in the three-month follow-up [Tables 4-6]. The cost-effectiveness ratio for MSICS was 13,215.50 compared to PE (CE ratio = 17,561.70) [Table 7]. However, the cost differential component in this study was uncharacteristically low with 10,043.81 Baht/case ($280) for MSICS and 11,590.72 Baht/case ($323) for phacoemulsification. This represented a saving of 1550 Baht ($43).[11] Gogate et al. and Muralikrishnan et al. reported that MSICS provider’s direct costs were (US $15.68, US $17.03).[1314] The pricing in India compared to even Thailand is interesting where this surgery costs nearly $300. In the UK, the total cost of PE was ≤359.89 with the postoperative care, and additional spectacle cost included in the costing by Jongsareejit et al.[11] estimated savings of about 290 million Baht (USD8.08 million) for Thailand if all 1.36 lakh cases were to receive MSICS at cost of about approximately 1790 million Baht (USD49.87 million) against 2080 million Baht (USD57.95 million) required or PE. FEMCAT study reported an incremental cost-effectiveness ratio of €10703 saved per additional patient who had treatment success with PE compared with FLACS, while incremental cost-effectiveness ratio who experienced success with MSICS represented a saving of US $121.10 in 2012 which is the equivalent of $152.51 in 2022 at cumulative price increase of 25.92% to adjust for inflation.[72930] This ICER of US $152.51 at current exchange value is €146.50. Hence MSICS is the most cost-effective technique among the three by interpolation. However, there is a paucity of high-quality data for economic analysis of cataract extraction techniques and more work is required on this subject. These findings have a bearing on the allocative decisions in healthcare policy, especially in public health and government-funded projects.

T6
Table 6:
Astigmatism Comparison between Phacoemulsification and MSICS
T7
Table 7:
Incremental Cost-Effectiveness Ratio (ICER) Difference Between Phacoemulsification and MSICS

Conclusion

Inadequate high quality costing data was obtainable for drawing clear inferences. The limited data available supports the contention that, from societal perspective, MSICS has the least costs followed by PE, ECCE-IOL, and FLACS. Heterogeneity among studies is very high. There have been very few robust studies to address the key questions of incremental cost-effectiveness ratio, cost, incremental cost, effectiveness, and utility for MSICS. The framework for cost analysis needs to amortize the costs over the lifespan of the machine while calculating costs. The authors recommend use of CUA and CEA over other techniques in the Indian setting, even though there is controversy over determination of quality-adjusted outcomes when data and resources are available. CEA can be inferred from CUA data theoretically, but CEA is useful when only intermediate outcomes of the compared alternatives are available. Future research in this area will be useful for allocative and technical efficiency measurements in policymaking.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

Supplementary Materials

Manual small incision cataract surgery (300)

small incision cataract surgery (1,341)

Economics/ (1,104,139)

Costs and Cost Analysis (273,004)

exp Economics, Hospital/ (140,387)

exp Economics, Medical/ (167,192)

Health Budgets/ (24,158)

Healthcare Budgets (12,839)

exp Models, Economic (51,904)

Health economics (1,715,982)

quality of life.tw. (149495)

Value of Life (5495)

Quality-Adjusted Life Years (7808)

quality adjusted life.tw. (6579)

disability adjusted life.tw. (1361)

Manual small incision cataract surgery (226)

small incision cataract surgery (561)

Economics/ (28,794)

Costs and Cost Analysis (578)

Economics, Hospital (71)

Economics, Medical (539)

Health Budgets (350)

Healthcare Budgets (278)

Models, Economic (1059)

Health economics (6414)

Value of Life (5495)

Quality-Adjusted Life Years (6703)

quality adjusted life.tw. (5668)

disability adjusted life.tw. (1061)

Search extended to all fields.

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Keywords:

Cost-effectiveness analysis (CEA); cost-utility analysis (CUA); health economics; incremental cost-effectiveness ratio (ICER); manual small-incision cataract surgery (MSICS)

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