A comparative cost analysis between two quick diagnosis units of different levels of complexity

We performed an analysis of costs using micro-costing techniques to determine and compare the costs associated with the diagnostic evaluation of ambulatory patients managed at two different quick diagnosis units in Barcelona. Our study showed that, even though statistical significance was not reached, the mean cost per patient of the unit of the tertiary hospital was moderately higher than the cost of the unit of the secondary center. However, costs of personnel and indirect costs of the Tertiary Unit, including both the monetary value and the percent contribution to the overall cost, were significantly higher.

Studies have shown that noninpatient care alternative strategies to hospital admission, which are best exemplified by daycare centers, hospitals-at-home, and, more recently, quick diagnosis units, effectively improve patient flow and ease the pressure on the availability of hospital beds [4,10,19]. Although quick diagnosis units have multiplied across tertiary and secondary Spanish hospitals during the last 15 years, reported studies analyzing their role as an alternative ambulatory care model to inpatient admission come just from a few centers [6,13,16,20,21]. In general, observational studies have concluded that the clinical efficiency of quick diagnosis units is similar to that of conventional hospitalization for diagnostic purposes but that the costs associated with the ambulatory management of these patients are lower than the cost applied to the same disorders in the inpatient setting [9–11,13,15,16,22,23].

With the exception of a cost minimization analysis comparing a quick diagnosis unit of a tertiary hospital versus hospitalization [15], studies analyzing the economic outcomes of these units have mainly involved informal cost evaluations. Two systematic reviews by authors from the United States analyzed all the reported articles about quick diagnosis units and found that the average cost savings from fixed costs of hospitalization ranged from €1764 to 2514 per patient in the quick diagnosis unit model compared with inpatient matched controls. Further, an economic saving of 7–8.76 inpatient beds per day was reported [5,7]. As far as we can tell, ours is the first study to compare the costs associated with the diagnostic assessment of patients managed at quick diagnosis units of hospitals of different level of complexity.

Though limited to the Spanish public system, a healthcare model similar to quick diagnosis units has been operating in the Scandinavian countries since the early 2010s. The differentiated approach works as an urgent referral pathway for patients with unspecific, serious symptoms, who are referred from primary care centers to the so-called ‘diagnostic centre’, a unit staffed with several specialists and equipped with a sort of facilities for diagnostic investigations. Although studies of patients assessed through this pathway have reported a number of high-quality indicators [24,25], no articles analyzing the incurred costs have been published to date.

In our study, the distribution of cost components of both units showed a similar pattern, with direct costs per patient, which include personnel costs, being the greatest contributors to overall costs (79.1% in the Tertiary vs 81.2% in the Secondary Unit). While diagnostic examinations accounted for the largest share of overall costs without significant differences (66.97% [(€386.77/577.50] in the Tertiary vs 70.27% [€277.37/394.70] in the Secondary Unit), the contribution of indirect costs per patient to the total cost, although significantly different, was relatively small (8.6 vs 3.3%, respectively). However, the differences in indirect and personnel costs observed in our study must be interpreted considering the similarities and differences of the two hospitals and their respective quick diagnosis units. Patients managed at the tertiary hospital are often referred from smaller, secondary hospitals including the second-level hospital reported here. Unlike the latter, the tertiary hospital has a full complement of services, highly specialized staff and high technological equipment. Although the clinical indications for referral and working methods of both units are similar, the volume of patients evaluated, the number of staff, and the contribution of staff time to the unit of the tertiary center are considerably greater. Yet the reported cost differences per patient cannot be explained by the volume of patients since results are shown per patient and not as a global count.

The analysis of clinical data revealed some salient findings. Time to diagnosis, which is considered an indicator of high-healthcare quality of quick diagnosis units [5–7], was significantly shorter in the tertiary center unit (8 vs 12 days, respectively; p < 0.0001). Although the cost per visit of the two units was similar (€182.8 in the Tertiary vs €184.6 in the Secondary Unit), we found significant differences in the total number of visits (i.e., first and successive appointments until diagnosis) including the ratio of successive/first visits, which were higher in the Tertiary Unit (3.1 and 2.1 vs 2.1 and 1.1, respectively). Accordingly, the differences in the mean cost per patient between the tertiary and secondary unit (€577.5 vs 394.7, respectively; p = 0.0559) should be mainly ascribed to the higher number of appointments in the former. While significant differences in indirect costs reflect the higher rate of operation and maintenance costs as expected for a unit located in a well-resourced daycare center, personnel costs are strongly linked to the number and ratio of visits.

When looking at the possible reasons for the higher number of visits in the Tertiary Unit, the following points must be considered. As shown in Table 1, the rate of referrals from the emergency department was 61.2% in the Tertiary Unit compared with only 17% in the Secondary Unit and these differences were more pronounced for patients referred for symptoms suggestive of cancer and patients with a diagnosis of cancer. In particular, while patients from the Tertiary Unit were significantly more likely to have symptoms suggestive of cancer as referral reason and cancer as final diagnosis, 65.1% (140/215) of them were referred to the unit after presentation to the emergency department. In contrast, the emergency department was the original referral source of only 15.9% (26/164) of patients with both suspected cancer and a cancer diagnosis assessed at the Secondary Unit (Tables 4 & 5). Furthermore, as partly reflected by these differences, patients from the secondary center unit were in general more likely to have milder and less acute or ‘urgent’ symptoms than those from the Tertiary Unit including, among others, unexplained fatigue, osteoarticular symptoms and nonspecific laboratory abnormalities. A former study showed that, with a lower number of visits, patients from the secondary center unit required fewer investigations to achieve a diagnosis than patients from the other unit [16], suggesting that their management was more straightforward. Specifically, patients from the Tertiary Unit were significantly more likely than those from the Secondary Unit to undergo endoscopies (17 vs 11%), ultrasonographies (15 vs 8%) and cytology/biopsy studies (21 vs 10%) and differences were more pronounced when analyzing diagnostic tests according to age groups and final diagnosis. For instance, among patients aged ≥65 years, those from the Tertiary Unit underwent significantly more CT scans (38 vs 25%), MRI examinations (13 vs 7%), ultrasonographies (19 vs 6%) and cytology/biopsy studies (26 vs 9%). Also, among patients with malignancy, those from the Tertiary Unit underwent, compared with Secondary Unit patients, a significantly higher number of CT scans (84 vs 69%), MRI examinations (40 vs 13%), ultrasonographies (50 vs 2%) and cytology/biopsy studies (79 vs 47%) [16]. Differences in cytology/biopsy studies are especially relevant since most of them involve invasive diagnostic procedures (mainly computed tomography- or ultrasound-guided biopsy or fine-needle aspiration cytology of abnormal areas of tissue and organs [e.g., liver, pancreas, lung and bone]) requiring admission to hospital for the day of the procedure.

Taken together, all these results suggest that a greater level of complexity of the medical disorders evaluated at the tertiary center unit most likely accounted for the differences in the volume and ratio of visits and the overall costs between the two units.

Our investigation found that the main driver of the cost differences between the quick diagnosis units of a tertiary and secondary hospital was the total number of visits and successive/first visits ratio. Owing to a higher number of visits, the mean cost per patient of the unit of the tertiary hospital was near-significantly higher than that of the secondary hospital unit. When costs per patient were split off into categories, significant differences were only observed for personnel or staff costs and indirect costs, which were higher in the tertiary center unit. A greater level of diagnostic and clinical complexity of the patients managed at this unit added to the own characteristics of the unit including the number of staff and the contribution of staff time were the leading factors contributing to the observed differences.

The results from this study justify additional research efforts to replicate and validate the favorable economic outcomes of these units in other healthcare settings and inform policy decisions on spending priorities that are relevant to hospital-based ambulatory care and quick diagnosis units.

All authors contributed to the study conception and design. Material preparation, data collection and analysis were performed by X Bosch, EMPalacín, MJM Peñas, Y Compta and Jordi Ramon. The first draft of the manuscript was written by X Bosch and all authors commented on previous versions of the manuscript. All authors revised the work critically for important intellectual content, approved the version to be published and agree to be accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved.

The authors have no relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript. This includes employment, consultancies, honoraria, stock ownership or options, expert testimony, grants or patents received or pending, or royalties.

No writing assistance was utilized in the production of this manuscript.

The study was carried out in line with the principles of the Declaration of Helsinki. Approvals were granted by the Research Ethics Committee of the Hospital Clínic of Barcelona and the network of hospitals to which Hospital Plató belongs to (Comitè d'Ètica de la Investigació Clínica [CEIC]-Unió Catalana d'Hospitals). Need for informed consent was waived due to the retrospective design of this study.

The authors certify that this manuscript reports original clinical trial data. Data reported in this manuscript are available within the article. Additional data from the study are available upon reasonable request.