Do independent treatment centers offer more value than general hospitals? The case of cataract care

Abstract Objective To identify differences between independent treatment centers (ITCs) and general hospitals (GHs) regarding costs, quality of care, and efficiency. Data Sources Anonymous claims data (2013‐2015) were used. We also obtained quality indicators from a semipublic platform. Study Design This study uses a comparative multilevel analysis, controlling for case mix, to evaluate the performance of ITCs and GHs for patients diagnosed with cataract. Data Collection Reimbursement claims were extracted from existing claims databases of the largest Dutch health insurer. Quality indicators were obtained by external agencies through a mixed‐mode survey. Principal Findings There are no stark differences in complexity of cases for cataract care. ITCs seem to perform surgeries more frequently per care pathway, but conduct a lower number of health care activities per surgical claim. Total average costs are lower in ITCs compared with GHs, but when adjusted for case mix, the differences in costs are lower. The findings with the adjusted quality differences suggest that ITCs outperform GHs on patient satisfaction, but patients’ outcomes are similar. Conclusion This finding supports the postulation—based on the focus factory theory—that ITCs can provide more value for cataract care than GHs.

KRUSE Et al. to better performance due to repetition, experience, and homogeneity of tasks. The aim would be to enhance the expertise of the health care provider and improve efficiency. These efficiency gains could then lower operational costs, 2,7 through standardization and by reallocating expertise and equipment to just one place.
Subsequently, reductions in overhead costs could be made possible. Furthermore, quality could be improved by means of routine and cultivating from continued learning. In line with Michael Porter's theory of Value-Based Health Care (VBHC) which defines value as patient-related outcomes relative to costs, 1 ITCs would theoretically achieve more value for the same procedure compared with full-service hospitals.
In many countries, the number of ITCs has risen steeply over the past decades. This increase is partly due to technological advances: more treatments can be reallocated to ambulatory care settings. Also, policy makers became more receptive toward ITCs, since many health care systems opted for a more market-driven system. In the United States, the number of Medicare-certified ITCs (called independent Ambulatory Surgery Centers in the US) doubled between 1991 and 2001 (1460-3371), but recently this growth has slowed down. 8,9 In the UK, the number of ITCs peaked in the mid-90s and has been declining since, 10 however, the total spending on the ITC sector increased with 39 percent between 2013/14 and 2016/17. 11 In the Netherlands, the number of ITC concerns has been growing steadily from 81 in 2008 to 241 in 2015. 6 ITCs started to emerge in the Netherlands when an act (1998) came into force allowing ITCs to provide reimbursable medical care for a limited array of treatments. That act was introduced in order to reduce waiting lists and to gain control over the for-profit clinics. 12,13 The formal distinction between ITCs and hospitals was abolished with the introduction of the Health Care Institutions Admission Act in 2005, which regulates the approval of reimbursable care providers. Now, both hospitals and ITCs are formally defined as medical specialist care providers; however, ITCs are still different in practice and categorized as different types of entity, by, for instance, patients associations, health insurers, and ITCs themselves. Some empirical evidence on the relative performance of ITCs exists, most of which comes from the United States. However, comparative studies scrutinizing cost and quality simultaneously are lacking. The studies that analyzed quality of care either find equivocal results 14,15 or find no clear medical quality advantages for ITCs over full-service hospitals. 14,16 Studies covering patients' experiences are also inconsistent, with one UK study finding no significant differences for the overall reported patients' experiences, 17 whereas one other study identified higher satisfaction rates among ITCs users compared with NHS facilities. 18 In contrast, the independent sector in the UK charged higher prices than NHS hospitals (unclear whether this disparity still exists), 19 and evidence points to the fact that ITCs in the UK are not always more efficient-only patients with hip or knee replacements had a shorter length of stay when treated in an ITC. 20 At the same time, findings from both the UK and the US suggest that ITCs might be cherry-picking and treat less-complex patients compared with hospitals. [20][21][22][23][24][25] From the demand side, it seems that the characteristics of patients seeking care from ITCs differ from those of patients seeking care from hospitals. The independent sector in the UK historically serves the interests of private practices of NHS consultants and target a more affluent clientele with additional amenities and shorter waiting lists. 3,20 Also in the United States, patients who are not insured via Medicaid more often chose to visit an ITC. 25 In the Netherlands, there is still a knowledge gap regarding the patterns of referral for patients visiting ITCs. One report from 2013 provides more insight on the motivations underlying patients' choice of health care provider: Patients going to ITCs often make the choice themselves (43 percent)-fewer of whom make a choice themselves to opt for care in a GH (38 percent). 26 Furthermore, not all ITCs are contracted by all health insurers, while GHs more often are contracted by all four major health insurers-with a contracting index of 0.53 for ITCs and 0.88 for hospitals. 27 Therefore, people with an indemnity health care insurance package will probably be more inclined to opt for ITCs. These insurance packages cover ITC care even when the ITC has no contract from this respective health insurer. From this perspective, people who could afford a more indemnity health care insurance package-people with a higher socioeconomic status (SES)-might have better access to ITCs. However, a recent report found no relationship between income and the choice for those insurance coverage that limits the choice of health care providers. 28 Another reason why there might be a certain selection of patients visiting ITCs is that, according to guidelines set by the Dutch health care inspectorate, ITCs should refrain from treating patients of ASA (American Society of Anesthesiologists) type III, which are patients with severe systemic diseases. 29 This study focuses on cataract care, a care modality often provided by ITCs. Cataract care is a classical example that illustrates the shift from inpatient care toward ambulatory care settings: "Cataract surgery has dramatically evolved from a procedure done almost exclusively as a routine inpatient procedure with a hospital stay up to 1 week to an outpatient operation with minimal limitations on the patient's postoperative activity." 30 In the Netherlands, most cataract surgical procedures are now outpatient and ITCs play a substantial role in delivering them. 12,31 There is a growing need to optimize cataract care delivery due to aging societies which means that the demand for cataract surgery will increase. 32 In 2006, the Netherlands implemented a number of market-oriented reforms of the health care system and the ITC enterprises subsequently grew. The focus factory theory would predict that ITCs would provide better value, but there remains uncertainty as to whether ITCs really do outperform GHs. To the best of our knowledge, this is the first study that scrutinizes the performance of ITCs in the Dutch health care system and assesses the added value of ITCs.
Cataract surgery provided by ITCs is compared with GHs over the period 2013 to 2015. Our aim was to provide insight into the case mix-adjusted differences between ITCs and GHs regarding costs, quality, and efficiency.

| Data
Our data are based on (anonymous) insurer claims and cover the period 2013-2015. We were able to include 4.5 million beneficiaries who were covered by the insurance company Achmea. This sample is highly representative: Achmea had a market share of 31.1 percent in 2015, making it the biggest health insurer in the Netherlands. 33 Achmea has the highest market share across a wide geographic area in the Netherlands, whereas three other largest health insurers are more geographically concentrated. Achmea claims data therefore offer a good degree of geographical representativeness. 34 Furthermore, the beneficiaries of the main health insurers reflect the diversity of the Dutch population, because the health insurers crosssubsidize costs among the more loss-making and more profit-generating clientele. 35 We extracted ophthalmological claims for people with a cataract diagnosis, based on the diagnosis code included in the claims data. All individual ophthalmological claims within a single year were obtained.
We use the annual cross-sectional inclusion of claims per patient to define the patients' care pathway. This means that all the ophthalmological claims that were claimed that year for one specific patient diagnosed with cataract were assigned to their patients' care pathway. Patients who received care from multiple providers during their care pathway were excluded from analysis, constituting between 1.6 percent and 2.0 percent of the patients. Data on quality of care were obtained from a platform that collects quality measures for health insurers. This specific database is owned and managed by the national database for insurers (Vektis). The quality data were obtained by means of a mixed-mode survey (not part of the current study), contracting two different external parties to manage the data collection. The national number of cataract surgeries per provider was attained from the same platform (Vektis). Data were linked through a unique identifier assigned by Vektis and are on concern level (a concern can have multiple locations). This unique identifier was also used to identify ITCs and GHs as the identifier codes are structured in such a way that the type of provider can be easily detected. Comparisons between GHs and ITCs are our main interest because academic and tertiary care hospitals deviate too much from the ITC organizational model, mainly because of their teaching objectives and their more complex patient base. Tertiary care and academic hospitals were categorized manually by means of the identifier codes. The descriptive statistics of these types can be found in the supplementary material.

| Study variables
In the Netherlands, providers are paid through a diagnostic-related groups system. Such groups are called "care products" (DRGs) and also include outpatient care. 36 For the care products used in this study, the price per DRG is determined through bilateral negotiations between health insurers and providers. Volume encompasses the total number of DRGs claimed in one care pathway, which could, for example, be consultation and diagnostic DRGs. Two types of cata- and minus zero indicates a lower than average SES neighborhood, whereas above zero indicates a higher SES than average. To assess possible multimorbidity, we grouped pharmaceutical claims of patients and used those as a proxy to identify whether they have one of the 27 chronic conditions included in the Dutch risk-adjusted contribution classification system. A patient was classified as multimorbid if they had two or more chronic conditions. We included ocular comorbidity as a separate confounder variable, since ocular comorbidity can have an impact on possible complications after cataract surgery. 39 To measure this, we used a proxy: diabetic type I and II and glaucoma-also obtained from the pharmaceutical claims. The models that include quality were adjusted for total surgical volume, accounting for the volume-quality relationship. 40 This includes the total number of cataract surgical claims per provider, so not solely the claims filled by Achmea.
Finally, we used patient-reported data from the Dutch Consumer Quality Index Cataract Questionnaire (CQI Cataract) to assess for quality of cataract surgery. 41 The quality indicators are the Net Promoter Score (NPS) and a patient-reported outcome measure (PROM). The NPS is a common management tool to measure patient satisfaction and asks the opinion of patients on "How likely is it that you would recommend this hospital or clinic for a cataract operation  We have NPS and PROM data for 2013 and 2014. However, for both years two different PROM scales were used: For 2013, a 4-point ordinal scale was used; for 2014, this was a 5-point scale, which makes comparisons between these two years troublesome.

| Statistical analysis
Our descriptive statistics outline the unadjusted interprovider differences regarding the characteristics of cataract patients (ie, case mix), type of surgical procedures, volume, price, and total costs. A mixedmodel approach is used to analyze the association between type of provider (ITCs vs GHs) and the dependent variables: number of health care activities (2015), total costs of claims (2013)(2014)(2015), and the quality parameters NPS and PROM (2013-2014). In the models, we accounted for clustering of patients within hospitals, including a random intercept for provider level, and adjusted for confounders such as case mix differences. Actual claims costs are skewed to the right; therefore, the total claims costs were logarithmically transformed in the multilevel model. The multilevel models are tested for better fit with the nontransformed cost models utilizing the Akaike information criterion (AIC). 42 The GHs are used as our reference category.   39 but on the other hand, when glaucoma has been detected early enough, a higher share of glaucoma patients does not necessarily reflect the complexity of those treated, because with medication their symptoms can be successfully suppressed. 43,44 In conclusion, these findings indicate that overall complexity of ITC patients for cataract care do not differ strongly from GHs.

| Volume
The number of DRGs and the number of surgical claims show that ITCs submit a slightly higher number of claims during a care pathway than GHs do (Table 1). Nevertheless, the average number of surgeries is higher within ITCs, with, on average, 0.91 cataract operations per care pathway, while GHs have an average of 0.84.

| Price and total claims costs
The descriptive statistics on charged DRG prices and total claims costs of the care pathway are also exhibited in Table 1 Tables S1-S4).
When adjusted for case mix, the total claims costs for cataract care in ITCs stay lower compared with GHs (Table 2)

| Efficiency
Efficiency in this study is defined as the number of activities in a surgical claim, where fewer activities are perceived as more efficient. Table 3 suggest that ITCs are more efficient in providing cataract surgery. ITCs carry out fewer health care activities within each surgical cataract DRG compared with GHs. The day care procedures (ie, a number of hours of nursing care spent within a nursing ward) are significantly shorter in ITCs. The number of anesthetic procedures also depicts a strong contrast: ITCs seem to do no anesthetic procedures.

Results in
The explanation for ITCs reporting almost no anesthetic procedures is because there are no health care activities for anesthetic eye drops.
(Anesthetic eye drops is a commonly used anesthetic for less-complex patients. 45 ) Only optometric therapy is a more frequent procedure among ITCs. This might well correspond with our reasoning that ITCs seem to be more efficient, since optometrists can serve as cheaper substitutes for ophthalmologists. 46 These differences between ITCs and GHs persist when adjusted for case mix (  Table 5 illustrates that, when the model controls for quality, the claims costs in ITCs remain lower compared with GHs for both 2013 and 2014 with 7 percent (exp(−0.07) ≈ 0.93). This is higher than the model with the adjusted claims costs ( Table 2; 5 percent difference), which does not control for quality differences, which means that ITCs perform better when quality of care is also taken into account.

| Patient value
Quality differences between ITCs and GHs demonstrate that ITCs score significantly better on the NPS compared with GHs. However, the dissimilarity of the PROM scores is marginal and inconsistent.
In other words, ITCs seem to perform better on patient satisfaction compared with GHs, but there are no differences in the patient-reported outcomes after cataract surgery. We find limited selection of low-severity patients for cataract surgery by ITCs, which is in line with the findings in Meyerhoefer et al, 22 but goes against the studies that do find case mix differences. 20,25 Furthermore, this study also seems to support that different quality indicators can show contrasting results. 15 A general trend that seems to emerge is that ITCs score better on patients' satisfaction, 18 but not on patient-reported outcomes of the treatment. 14 This study has some strengths. We were able to use claims data from a big sample of the Dutch population utilizing multiple years.

| D ISCUSS I ON
Secondly, this study is one of the first that empirically studies the relative performance of the ITC market in a number of areas (ie, costs, quality and efficiency). Thirdly, this study takes a broader perspective of the patients' care pathway, instead of only comparing surgical claims. Fourthly, we were able to separate claim reimbursements from actual activities, identifying process efficiency differences between ITCs and GHs.
Our study is also subject to some limitations. (a) The quality indicators used in this study were not optimal. Quality data for cataract  Note: Controlled for academic hospitals, tertiary care hospitals, SES, gender, multimorbidity, ocular comorbidity, aged 85 or older, high and low volume providers, 2 or more operations, type of operation (complex). Standard errors in parentheses. a Controlled for NPS and PROM. b Controlled for log costs.
conclusion, for some elective surgeries ITCs could potentially enhance value of modern health care systems, but policy makers do need to be alert to possible adverse effects.