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Comparative Analysis of Outcomes and Costs Following Open Radical Cystectomy Versus Robot-Assisted Laparoscopic Radical Cystectomy: Results From the US Nationwide Inpatient Sample
European Urology, 6, 61, pages 1239 - 1244
Although robot-assisted laparoscopic radical cystectomy (RARC) was first reported in 2003 and has gained popularity, comparisons with open radical cystectomy (ORC) are limited to reports from high-volume referral centers.
To compare population-based perioperative outcomes and costs of ORC and RARC.
Design, setting, and participants
A retrospective observational cohort study using the US Nationwide Inpatient Sample to characterize 2009 RARC compared with ORC use and outcomes.
Outcome measurements and statistical analysis
Propensity score methods were used to compare inpatient morbidity and mortality, lengths of stay, and costs.
Results and limitations
We identified 1444 ORCs and 224 RARCs. Women were less likely to undergo RARC than ORC (9.8% compared with 15.5%, p = 0.048), and 95.7% of RARCs and 73.9% of ORCs were performed at teaching hospitals (p < 0.001). In adjusted analyses, subjects undergoing RARC compared with ORC experienced fewer inpatient complications (49.1% and 63.8%, p = 0.035) and fewer deaths (0% and 2.5%, p < 0.001). RARC compared with ORC was associated with lower parenteral nutrition use (6.4% and 13.3%, p = 0.046); however, there was no difference in length of stay. RARC compared with ORC was $3797 more costly (p = 0.023). Limitations include retrospective design, absence of tumor characteristics, and lack of outcomes beyond hospital discharge.
RARC is associated with lower parenteral nutrition use and fewer inpatient complications and deaths. However, lengths of stay are similar, and the robotic approach is significantly more costly.
Keywords: Bladder cancer, Cost, Cystectomy, Outcomes, Robotic surgery.
Despite advances in surgical technique, radical cystectomy remains a morbid procedure, with complications ranging from 30% to 65%  and . Many patients intuitively perceive minimally invasive approaches as reducing complications compared with conventional open operations and prefer minimally invasive procedures because of smaller incisions requiring less analgesics and shorter hospital stays, even at greater cost. The robotic surgical platform shortens the learning curve for open surgeons transitioning to minimally invasive surgery  . Advantages of robotic technology compared with traditional laparoscopy include a three-dimensional view of the operative field and the absence of a fulcrum effect with seven compared with four degrees of freedom of wristed instrument movement, which increases the ease of intracorporeal suturing, eliminates surgeon tremor, and provides ergonomic benefits. Thus the robotic surgical platform facilitates a minimally invasive approach to radical cystectomy.
Despite the technical advantages of robotic technology, there are few comprehensive comparative studies of robot-assisted laparoscopic radical cystectomy (RARC) and open radical cystectomy (ORC). To date, the largest series compared 104 ORCs with 83 RARCs and demonstrated fewer complications with the robotic approach  , and the only randomized study, comparing 20 ORCs with 21 RARCs, found lower blood loss and analgesic requirements, earlier return to bowel function, and demonstrated comparable lymph node yields  . However, most studies, including the aforementioned, arise from high-volume referral centers and may not reflect practice patterns and outcomes generalizable on a population-based level. Therefore, the objectives of our population-based study are to characterize patterns of care and to compare inpatient outcomes and costs of RARC and ORC.
2.1. Data source
Subjects were identified from the US Healthcare Cost and Utilization Project (HCUP) Nationwide Inpatient Sample (NIS), sponsored by the Agency for Healthcare Research and Quality  . The NIS is a 20% stratified probability sample that encompasses approximately 8 million acute hospital stays per year from 1050 hospitals in 44 states. It is the largest all-payer inpatient care observational cohort in the United States and represents approximately 90% of all hospital discharges.
2.2. Study cohort
During 2009, there were 7 810 762 subjects within the NIS. Using NIS discharge weights, these subjects represented 39 434 956 admissions. We used the International Classification of Diseases, 9th Revision (ICD-9), procedure code 57.71 associated with bladder cancer (BCa) diagnosis codes 188.0–188.6, 188.8, 188.9, and 233.7 to identify radical cystectomy. The ICD-9 modifier for robotic assistance, 17.4x, initiated on October 1, 2008, was used to identify RARC. Also, concurrent ICD-9 54.21 and 54.51 without a robotic-assistance modifier were used to identify cases of pure laparoscopic radical cystectomy. However, only 55 laparoscopic radical cystectomies were identified, and they were excluded because of inability to power adjusted analyses.
For each procedure, we examined patient- and hospital-level characteristics that may be associated with outcomes. Patient-level characteristics included age, gender, race, number of comorbidities based on the Elixhauser method  , ZIP code–based median income, primary payer, and use of ileal conduit or continent (orthotopic neobladder or continent cutaneous reservoir) urinary diversion identified using ICD-9 56.51 or 57.87. Hospital characteristics included non-teaching compared with teaching, bed size, US Census region, and annual radical cystectomy volume.
Pelvic lymph node dissections were identified using ICD-9 40.3 and 40.5. ICD-9 diagnosis and procedure codes ( Table 1 ) were used to identify blood transfusions, parenteral nutrition use, and inpatient complications (cardiac, respiratory, genitourinary, vascular, wound, miscellaneous medical, and miscellaneous surgical)  . NIS-specific outcomes included death, hospital lengths of stay, discharge disposition (routine [home] vs home health care vs other [rehabilitation, skilled nursing facility, and so on]), and total costs. Costs were derived from total hospital charges using the HCUP cost-to-charge ratio, which allows conversion of charges to the amount that hospitals are reimbursed  .
|Category||Diagnosis codes||Procedure codes|
|Blood transfusion||V58.2||99.00, 99.02, 99.03, 99.04|
|Cardiac||410.xx, 402.01, 402.11, 402.91, 428.xx, 427.5, 997.1||–|
|Respiratory||518.0, 514, 518.4, 466.xx, 480.xx, 481, 482.xx, 483.xx, 485, 486, 518.5, 518.81, 518.82, 799.1, 997.3||–|
|Genitourinary||590.1x, 590.2, 590.8x, 590.9, 591, 593.3, 593.4, 593.5, 593.81, 593.82, 595.89, 596.1, 596.2, 596.6, 997.5||55.02, 55.03, 55.12, 55.93, 55.94, 59.93, 97.61, 97.62, 56.1, 56.41, 56.74, 56.75, 56.81, 56.84, 56.86, 56.89, 56.91|
|Wound||567.xx, 998.3, 998.5x, 998.6||54.61, 54.1x, 54.91, 54.0, 59.19|
|Vascular||415.1, 451.1x, 451.2, 451.81, 451.9, 453.8, 453.9, 997.2, 999.2, 444.22, 444.81, 433.xx, 434.xx, 436, 437.xx||–|
|Miscellaneous medical||584.xx, 586, 785.5x, 995.0, 995.4, 998.0, 999.4, 999.5, 999.6, 999.7, 999.8, 457.8, 560.1, 560.8x, 560.9, 997.4, 353.0, 354.2, 723.4, 955.1, 955.3, 955.7, 955.8, 955.9, 531.xx, 532.xx, 533.xx, 782.4, 573.8||–|
|Miscellaneous surgical||599.1, 596.1, 596.6, 565.1, 569.3, 569.83, 569.4x, 998.1x, 998.83, 998.9, 998.2, 998.4, 998.7, 604.0, 956.0, 956.1, 956.4, 956.5, 956.8, 956.9, 902.50, 902.51, 902.52, 902.53, 902.54, 902.59||46.03, 46.04, 46.10, 46.11, 46.14, 48.4x, 48.5, 48.6x, 48.7x, 48.9x|
ICD-9 = International Classification of Diseases, 9th revision.
2.4. Statistical analysis
Stratification, clustering, and survey weights were used in accordance with the NIS sampling design. Demographic characteristics were compared between RARC and ORC using complex survey chi-square tests  . Propensity score methods  were used to compare RARC and ORC with respect to lymphadenectomy use, inpatient morbidity and mortality, transfusions, parenteral nutrition use, discharge disposition, lengths of stay, and costs. Propensity score methods permit control for observed confounding factors that may influence both group assignment (RARC or ORC) and outcomes using a single composite measure, and they attempt to balance patient characteristics between groups. We used a logistic regression model to calculate the propensity (probability) of undergoing RARC or ORC based on all covariates previously described and then weighted each subject's data based on the inverse propensity of being in one of the two treatment groups  . In the model, age and hospital cystectomy volume were included as continuous variables, whereas all other variables were categorical. In our propensity-adjusted analyses, there were eight primary outcomes. Six were categorical: lymphadenectomy use, death, inpatient complications, transfusions, parenteral nutrition use, and discharge disposition. Age and comorbidity were assessed as continuous variables. Secondary outcomes included inpatient complication subtypes. All analyses were performed with SAS v.9.2 (SAS Institute Inc., Cary, NC, USA), and all tests were considered statistically significant at p < 0.05.
3.1. Characteristics of study sample
There were 224 RARCs and 1444 ORCs performed at 234 hospitals within the NIS, representing 1144 RARCs and 7168 ORCs after incorporating NIS survey weights. Thus, RARCs made up 13.3% of radical cystectomies in 2009. Demographics of the study population are shown in Table 2 .
|Before propensity weighting||After propensity weighting|
|Total||Open||Robotic||p value||Total||Open||Robotic||p value|
|Age, yr, median (IQR)||69 (68–70)||69 (68–70)||1.000||70 (69–71)||72 (69–75)||0.232|
|Gender, no. (%)|
|Male||7086||6055 (84.5)||1031 (90.2)||0.048||6966||6872 (83.7)||94 (91.2)||0.053|
|Female||1226||1114 (15.5)||112 (9.8)||1346||1337 (16.3)||9 (8.9)|
|Race, no. (%)|
|White||5835||5135 (71.6)||700 (61.2)||0.497||1730||6519 (79.4)||63 (61.1)||0.053|
|Nonwhite||801||680 (9.5)||122 (10.6)||6582||1690 (20.6)||40 (38.9)|
|Missing||1676||1354 (18.9)||323 (28.2)||–||–||–||–|
|Comorbidity, no. (%)|
|0–2||4756||4024 (56.1)||732 (64.0)||0.054||4310||4253 (51.8)||57 (55.3)||0.612|
|≥3||3556||3144 (43.9)||412 (36.0)||4002||3956 (48.2)||46 (44.7)|
|Ileal conduit, no. (%) *||6343||5477 (76.4)||866 (75.7)||0.871||6610||6530 (79.6)||80 (77.9)||0.766|
|Primary payer, no. (%)|
|Private||2483||2065 (28.8)||418 (36.5)||0.274||2154||2132 (26.0)||23 (22.2)||0.682|
|Medicare||5118||4470 (62.4)||647 (56.6)||5459||5387 (65.6)||72 (70.1)|
|Medicaid/other||712||633 (8.8)||79 (6.9)||698||690 (8.4)||8 (7.8)|
|Zip code income, no. (%)|
|<$39 000||1681||1538 (21.9)||143 (12.9)||0.073||2259||2246 (27.4)||13 (12.4)||0.015|
|$39 000–47 999||2236||1901 (27.1)||335 (30.3)||2061||2037 (24.8)||24 (23.4)|
|$48 000–62 999||2234||1897 (27.0)||338 (30.5)||2129||2102 (25.6)||27 (26.2)|
|≥$63 000||1974||1684 (24.0)||291 (26.3)||1863||1824 (22.2)||39 (38.0)|
|Hospital type, no. (%)|
|Non-teaching||1848||1800 (26.1)||49 (4.3)||<0.001||4098||4069 (49.6)||28 (27.6)||0.053|
|Teaching||6182||5091 (73.9)||1091 (95.7)||4214||4140 (50.4)||75 (72.4)|
|Hospital bed size, no. (%)|
|Small||1165||708 (10.3)||457 (40.1)||<0.001||2612||250 (3.1)||12 (11.3)||0.009|
|Medium||1354||1178 (17.1)||175 (15.4)||1358||1348 (16.4)||10 (9.7)|
|Large||5511||5005 (72.6)||507 (44.5)||6692||6610 (80.5)||81 (79.1)|
|Hospital region, no. (%)|
|Northeast||1555||1220 (17.0)||335 (29.3)||0.129||1055||1038 (12.7)||17 (16.6)||0.800|
|Midwest||3035||2676 (37.3)||359 (31.4)||2897||2856 (34.8)||41 (40.1)|
|South||1829||1734 (24.2)||95 (8.3)||2916||2886 (35.2)||30 (29.0)|
|West||1893||1539 (21.5)||354 (31.0)||1444||1429 (17.4)||15 (14.3)|
|Hospital volume, median (IQR)||18 (16–20)||37 (36–38)||<0.001||10 (9–11)||12 (5–19)||0.582|
* Non–ileal conduit includes orthotopic neobladder or continent cutaneous reservoir identified with International Classification of Diseases, 9th Revision, code 57.87.
IQR = interquartile range.
Age, race, comorbidity, urinary diversion use, insurance payer type, income, and regional utilization were similar by surgical approach. The median age of both cohorts was 69 yr (p = 0.999), and 75.7% of RARCs and 76.4% of ORCs used ileal conduits (p = 0.871). Women were less likely to undergo RARC than ORC (9.8% and 15.5%, p = 0.048). Additionally, 95.7% of RARCs and 73.9% of ORCs were performed at teaching hospitals (p < 0.001). However, the robotic approach accounted for a larger proportion of radical cystectomy cases at small compared with large hospitals (p < 0.001). Median annual hospital radical cystectomy volume was higher among institutions performing RARCs than ORCs (37 compared with 18, p < 0.001).
Unadjusted and adjusted outcomes are presented in Table 3 . While secondary complication subtypes did not differ significantly in adjusted analyses, subjects undergoing RARC compared with ORC experienced fewer deaths (0% and 2.5%, p < 0.001) and fewer complications (49.1% compared with 63.8%, p = 0.035, excluding death). There was no difference in RARC compared with ORC blood transfusion use (32.0% and 37.9%, p = 0.448). While parenteral nutrition use was lower with RARC than with ORC (6.4% compared with 13.3%, p = 0.046), the likelihood of routine discharge (19.4% compared with 28.2%, p = 0.099) and median lengths of stay (8 d for both, p = 0.999) were similar. Moreover, concurrent pelvic lymph node dissection use did not differ significantly for RARC compared with ORC (76.8% and 67.0%, p = 0.248). Finally, RARC costs were greater than ORC costs (median $28 100 compared with $24 303, p = 0.023).
|Primary outcomes||Open n = 7168||Robotic n = 1144||p value||Open||Robotic||p value|
|Inpatient complications||4318 (60.2)||541 (47.3)||0.004||63.8||49.1||0.035|
|Blood transfusion||2966 (41.4)||351 (30.7)||0.075||37.9||32.0||0.448|
|Parenteral nutrition||906 (12.6)||82 (7.2)||0.025||13.3||6.4||0.046|
|Routine discharge||1924 (27.5)||342 (29.9)||0.726||28.2||19.4||0.099|
|Lymph node dissection||4954 (69.1)||987 (86.3)||<0.001||67.0||76.8||0.248|
|Continuous||Median (IQR)||Median (IQR)|
|Length of stay, d||8 (7.8–8.2)||7 (6.6–7.4)||<0.001||8 (7.8–8.2)||8 (7.2–8.8)||0.999|
|Costs, $|| 24 607|
(23 741–25 474)
| 30 563|
(28 911–32 215)
|<0.001|| 24 303|
(23 265–25 341)
| 28 100|
(25 015–31 185)
|Cardiac||645 (9.0)||55 (4.8)||0.013||10.3||5.6||0.110|
|Respiratory||1282 (17.9)||144 (12.6)||0.067||18.4||15.2||0.421|
|Genitourinary||798 (11.1)||91 (8.0)||0.243||11.3||6.6||0.112|
|Wound||526 (7.3)||48 (4.2)||0.059||7.6||4.6||0.185|
|Vascular||258 (3.6)||31 (2.7)||0.636||3.6||1.8||0.316|
|Miscellaneous medical||3115 (43.5)||380 (33.3)||0.035||47.6||35.9||0.096|
|Miscellaneous surgical||739 (10.3)||69 (6.0)||0.043||10.3||6.7||0.217|
IQR = interquartile range.
There is an absence of comparative population-based studies of RARC and ORC; most existing studies are single-surgeon series, whereby investigators may receive educational or research funding and/or serve on the speakers’ bureau for the device manufacturer. Moreover, estimates of robot-assisted surgery use are provided primarily by Intuitive Surgical (Sunnyvale, CA, USA), the manufacturer of the da Vinci robotic platform  . The rapid adoption of robot-assisted surgery for prostate cancer and other diseases has called into question whether, in the absence of clear evidence demonstrating significant superior clinical outcomes, the benefits of this technology justify the greater costs compared with competing open surgical approaches  .
Our study is the first population-based comparative study of RARC and ORC and has several important findings. First and most strikingly, there were no deaths associated with RARC compared with a 2.5% ORC inpatient mortality. Our ORC mortality is similar to the range of 0.3–3.9% from published series  . Population-based studies similarly demonstrated lower inpatient mortality for robotic than for open radical prostatectomy (0% and 0.2%) and nephrectomy (0% and 1.4%)  and . However, our difference in RARC and ORC mortality is more pronounced, likely because of greater morbidity of radical cystectomy compared with radical prostatectomy and nephrectomy. While we found zero deaths with RARC, our findings must be interpreted in the context of the possibility that RARC perioperative mortality may increase with greater sampling. Additionally, the median annual hospital volume of 18 cases per year for ORC is significantly lower than 50 cases per year, which has been shown to be associated with lower mortality rates compared with lower surgical volumes  . Patients who die of BCa lose an average of 12 yr of income-producing life, valued at $200 000–500 000 per death  . Curtailing the life of BCa survivors as fatal sequelae of an elective surgical procedure exacerbates this significant loss.
Second, RARC was associated with fewer inpatient complications than ORC. While no one complication reached statistical significance, likely because of the low power for individual complication subtypes, the cumulative incidence of complications was lower for RARC. This finding suggests that no one complication subtype was driving this difference, which is consistent with prior studies of population-based studies that demonstrated fewer complications with the robotic than the open approach in inpatient settings , , , and . Additionally, despite the World Health Organization and Société Internationale d’Urologie consensus that orthotopic diversion results in the lowest complication rates, >75% of all cystectomies used ileal conduit  . This has potential negative implications in the quality of cystectomy care and outcomes.
Third, there was no difference in the lengths of stay for RARC and ORC. While parenteral nutrition use was lower with RARC, consistent with comparative colorectal studies  and single-center series for laparoscopic radical cystectomy  and RARC  demonstrating earlier return of bowel function with minimally invasive approaches, this lower use did not appear to affect discharge disposition or hospital lengths of stay on a population-based level.
Fourth, RARC is more costly than ORC. Proponents of ORC argue that RARC incurs greater costs in the absence of definitive clinical benefit, which has been estimated to be approximately $1600 more per case in direct costs than ORC  . There are few studies on comparative cystectomy costs, and all arise from small single-center series. Thus, some contend that estimates reflect the experience of high-volume referral centers  . In our population-based study, we have found that the inpatient cost difference significantly exceeds this figure. While our hospital costs exclude surgeon fees and robotic system acquisition/maintenance costs, surgeon fees for robotic and open surgical procedures are similar. For instance, for radical prostatectomy, the most commonly performed robot-assisted procedure, physician reimbursement for robot-assisted compared with open radical prostatectomy differs by $107  .
Fifth, women were less likely to undergo RARC than men. Female gender has previously been described as being associated with greater risk for cystectomy surgical morbidity  . Gender-based variation in surgical anatomy and need for anterior exenteration increase female cystectomy case complexity and may lead to female patient selection for ORC. However, there are potentially other confounders associated with gender that we were unable to control for, such as differences in body mass index or smoking status.
Sixth, RARCs were performed almost exclusively at teaching hospitals. Similarly, almost three-quarters of ORCs were also performed at teaching hospitals. Given the preponderance of RARCs at teaching hospitals, it may seem contradictory that smaller hospitals were more likely to perform RARCs than ORCs. However, smaller teaching hospitals were among the early adopters of robotic assistance for prostate cancer and heart surgery, and they are some of the highest-volume centers for robotic surgery  .
Finally, despite concerns that the robotic unit has limited maneuverability to perform an extended lymph node dissection  , subjects undergoing RARC were no less likely to undergo lymph node dissection than subjects undergoing ORC. Use of lymph node dissection during radical cystectomy is associated with better disease-specific survival, and performing an extended lymph node dissection during radical cystectomy has been suggested as a quality indicator  . RARCs were more commonly performed at teaching hospitals, where there may be greater surgeon adherence to oncologic practice guidelines compared with non-academic practice settings. While it is concerning that 33.0% of ORC patients and 23.2% of RARC patients did not undergo lymph node dissection, this finding is consistent with population-based studies of the US Surveillance Epidemiology and End Results tumor registries, where lymph node dissection was not performed in 21% of radical cystectomies  . Although we are unable to evaluate the yield and extent of lymph node dissections, others have shown that RARC lymph node yields are comparable to those of ORC  and .
Our study must be interpreted within the context of the study design. First, administrative data are designed for billing purposes and may lack detailed clinical information, such as continent diversion type in our study. While these data have been shown to have high sensitivity in capturing surgical complications  , we were unable to assess the severity or grade of these complications. Second, NIS characterizes only inpatient outcomes, and we were unable to assess readmissions, late complications, or earlier return to activities of daily living/work. Third, because of the absence of tumor characteristics and detailed clinical history, we were unable to assess body mass index, whether chemotherapy or irradiation was given prior to radical cystectomy, extent of lymph node dissection and yield, or differences in oncologic outcomes. However, the largest single-center comparative study found fewer RARC complications in the setting of similar pathologic stage compared with ORC  . Additionally, organ-confined versus non–organ-confined disease was not an independent predictor of complications, whereas surgical approach was predictive on multivariable analyses. Large single-center ORC series have not shown associations between tumor stage with early complications  , and a population-based study of 1126 ORCs found that pathologic stage did not affect 90-d reoperation or mortality  . Finally, we were unable to assess the effect of surgeon volume independent of hospital volume.
Compared with ORC, RARC is associated with less parenteral nutrition use and fewer inpatient complications and deaths. However, there was no difference in length of stay, and the robotic approach was significantly more costly.
Author contributions: Jim C. Hu had full access to all the data in the study and takes responsibility for the integrity of the data and the accuracy of the data analysis.
Study concept and design: Yu, Hu.
Acquisition of data: Yu, Hevelone, Hu.
Analysis and interpretation of data: Yu, Hevelone, Lipsitz, Kowalczyk, Nguyen, Choueiri, Kibel, Hu.
Drafting of the manuscript: Yu, Hevelone, Lipsitz, Kowalczyk, Nguyen, Choueiri, Kibel, Hu.
Critical revision of the manuscript for important intellectual content: Yu, Hevelone, Lipsitz, Kowalczyk, Nguyen, Choueiri, Kibel, Hu.
Statistical analysis: Hevelone, Lipsitz.
Obtaining funding: Yu, Hu.
Administrative, technical, or material support: Hu.
Other (specify): None.
Financial disclosures: Jim C. Hu certifies that all conflicts of interest, including specific financial interests and relationships and affiliations relevant to the subject matter or materials discussed in the manuscript (eg, employment/affiliation, grants or funding, consultancies, honoraria, stock ownership or options, expert testimony, royalties, or patents filed, received, or pending), are the following: Dr. Yu receives salary support from the American Urological Association Foundation Research Scholars Award and the Robert and Kathy Salipante Minimally-Invasive Urologic Research Fellowship, and Dr. Hu receives salary support from the US Department of Defense Physician Training Award W81XWH-08-1-0283.
Funding/Support and role of the sponsor: None.
Acknowledgment statement: The authors acknowledge the efforts of the Healthcare Cost and Utilization Project in the creation of the NIS database, and the American Urological Association Research Scholars Program for supporting this work.
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a Division of Urology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA
b Center for Surgery and Public Health, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA
c Department of Urology, Georgetown University Hospital, Washington, DC, USA
d Department of Radiation Oncology, Lank Center for Genitourinary Oncology, Dana-Farber Cancer Institute, Harvard Medical School, Boston, MA, USA
e Department of Medicine, Lank Center for Genitourinary Oncology, Dana-Farber Cancer Institute, Harvard Medical School, Boston, MA, USA
f Institute of Urologic Oncology, Department of Urology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, USA
© 2012 European Association of Urology, Published by Elsevier B.V.