The original purposes of DRGs were to enable meaningful comparisons and facilitate hospital management by improving the effectiveness and efficiency of health care [2, 14]. It is now a principle type of hospital payment system in many developed and developing countries [2, 15]. The characteristics of a DRG-based payment system are an exhaustive patient case classification system along with its associated payment formula. Thus, patients within the same DRG scheme are expected to be clinically and economically similar, undergo a similar treatment, and be reimbursed similarly. The successful implementation of the DRG payment system across countries and disease categories has been reported elsewhere in the literature [16–18].
Over the years, LC has become the treatment of choice for AC, and it is one of the most common procedures performed by acute care surgeons [19, 20]. The diagnosis and treatment of AC have progressively been standardized [13, 21, 22]. Currently, LC for AC has proven efficacious and safe. A number of randomized trials have shown consistent results: the mean hospital stay is between 3 and 5 days, and the incidence of serious complications is approximately 6%, with almost no reports of mortality [8, 23, 24]. Such consistency provided a solid rationale to incorporate AC into the DRG payment system because the overall cost is expectable and the odds of having an unexpectedly high cost are low. In line with these studies, our results also showed that although compared to patients in DRG-1, patients in DRG-2 had more complicated comorbidities (CCI ≥ 3), higher surgical risks (ASA ≥ 3), and more severe inflammation (higher CRP levels), their postoperative outcomes were similar. There were no differences in terms of postoperative stay, ICU stay or total length of stay between the two groups. The complication rates were also similar. This supports the current concept that LC for AC is an effective and safe modality that, following adequate preparation, the surgical outcomes are generally consistent and expectable regardless of differences in preoperative physical conditions.
When each AC grade within a DRG scheme was compared, patients with severe AC in DRG-1 had a longer postoperative stay and ICU stay than those with mild and moderate AC. On the other hand, such differences were less significant in DRG-2: only ICU stay, not postoperative stay, was longer in patients with severe AC. This could in part be explained by the fact that, regardless of the severity of AC, patients with more complex comorbidities required a certain amount of time to recover from surgery. Therefore, these patients should be reimbursed by a DRG scheme different from those without major comorbidities.
Based on the above principle, the TW-DRG covered the cost for inpatient care, and the incremental payment for the LC DRG scheme was based on “comorbidities and complications”. This was similar to DRGs of many other countries, in that the urgent or emergent nature of the procedure was not considered a factor for the increased costs [3, 9]. However, this policy has been under debate. Schneider et al. [25] argued that surgeons are likely to be discouraged from treating emergency patients if they cannot be compensated properly for the increased risks and challenges. In an earlier investigation, Chen et al. [9] reported that the total cost for urgent cholecystectomies was approximately 90% higher than that for elective cholecystectomies. They suggested that such increased costs and resource consumption should be recognized when the DRG authorities were establishing reimbursement rates [9]. Nonetheless, following decades of DRG implementation and revision, it appears that patient comorbidities are still the decisive factor that accounts for the costs and resource consumption within the same disease category. For example, a recent study by Boehme et al. [26] showed that patient comorbidities increased postoperative resource utilization after LC. The authors suggested that comorbidities play a major role in clinical risk stratification and should be considered in the bundled reimbursement package [26]. Similar conclusions can be found in the literature for other diseases [27]. In one study regarding the treatment of intertrochanteric femur fractures, there was a net profit for treating more comorbid patients but a net deficit for treating healthier patients [28]. Likewise, our results also showed that patients in DRG-2 (with comorbidities) had higher margins per patient than those in DRG-1 (without comorbidities). This finding is most likely due to the design of the weight-adjusted reimbursement system (e.g., weighted by the CMI of the hospital), which provide incentives for hospitals to treat patients with more comorbidities.
From the point of view of well-developed and very high-income countries, the average profit that a hospital gained per patient in this study seems to be very low (24,993 TWD, approximately USD 850, Table 3). This result is probably due to the design of Taiwan’s NHI system. Taiwan’s NHI is a single payer, population-based public insurance system that provides universal healthcare coverage for virtually every Taiwanese individual [29]. The universal NHI system has been a success, and it has gained worldwide attention due to its low rates and high quality [11, 30]. The national health expenditures have been held to less than 7% of GDP, which compares very favorably to the United States' 17.8% and approximately 10% of other high-income countries as of 2016 [29, 31–34]. Even with such a constrained budget, hospitals have still managed to provide efficient and quality medical services, as demonstrated by the short period of admission to operation and a short LOS. Furthermore, as shown in Figs. 1 and 2, the claims for most of the cases managed to fall into the lower half of sector B, which is the “most profitable location”.
There are several limitations to this study. First, the current study was a retrospective review of a single-center experience, not necessarily reflecting the financial results of other hospitals operating under the same system. However, as our institution is a medical center that routinely receives difficult and complicated cases from around the country, our results showed that DRGs can be well adopted under such settings for acute care surgery. Second, it is quite natural that DRG systems across countries are very heterogeneous because of different classification variables and algorithms. The costing methodologies are also different to address the specific financial structure of each country [3, 35]. However, surgeons, hospital managers and even DRG authorities in each country may exchange experiences for new perspectives to optimize their existing DRG systems.