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Database of surgical procedures: a summary of selected characteristics of the surgical population of the University of Puerto Rico-affiliated hospitals.

Objective: To evaluate the age distribution and selected characteristics of the cases recorded in the University of Puerto Rico (UPR) Surgical Database.

Methods: All the surgical cases (from 1/1/2013 to 12/31/2013) in the Surgery Department's database were examined. This database collects patient and procedural information from the surgical services of the UPR-affiliated hospitals (University District Hospital; University Pediatric Hospital; UPR Carolina Hospital; Oncologic Hospital [Dr. I. Gonzalez Martinez], Pavia Hospital-colorectal service; and Auxilio Mutuo Hospital-colorectal and oncologic services). The patients in the group were subdivided by age (<65 or [greater than or equal to]65 years). The difference between age groups was evaluated using a chi2, t-test, or ANOVA, whichever was appropriate, with a p- value less than 0.05 being considered significant.

Results: Information on 5,263 surgical patients was available for the study period. The mean age was 48 years ([+ or -] 23 years), with 28% of the patients being over 65 years of age. The age group with the highest rate of surgery was that of 61 to 70 years. The gender distribution was found to be similar to that of the general population: 55%, female, and 45%, male. The distribution by surgical service was as follows: general surgery, 32%; colorectal surgery, 21%; oncologic surgery, 22%; and others, 25%. The surgeries were elective in 87% of the cases and emergency procedures in 13% of them. Complications were reported in 3% of the cases; the mortality rate was 1%.

Conclusion: Despite the fact that only 14% of our population was 65 years of age or older, 28% of the patients requiring surgery were in this age group. Older patients now represent a significant proportion of the surgical workload. Our study found that 75% of the surgical procedures performed were in the areas of general, oncologic, and colorectal surgery. [P R Health Sci J 2016;35:26-29]

Key words: Surgery, Database, Population aging


Objetivo: Evaluar distribucion por edad y caracteristicas de casos quirurgicos en la Base de Datos de la Universidad de Puerto Rico (UPR). Metodos: Examinamos todos los casos quirurgicos entrados a la Base de Datos entre 1/1/2013 y 12/31/2013. Esta base de datos contiene informacion sobre los casos quirurgicos realizados por los hospitales afiliados a la UPR (Hospital de Distrito Universitario, Hospital Universitario Pediatrico, Carolina-UPR, Oncologico, PaviaColorectal, Auxilio Mutuo-Colorectal/Oncologico). El grupo se subdividio por edad entre los <65 y los [greater than or equal to]65 anos. Evaluamos diferencias entre grupos con la prueba Chi2, prueba t, o ANOVA, consideramos p<0.05 estadisticamente significativo. Resultados: Durante el periodo del estudio se realizaron 5,263 casos quirurgicos. La edad media fue de 48[+ or -]23 anos y 28% del grupo tenia 65 anos o mas. El intervalo mas grande fue el de 61 a 70 anos. La distribucion por genero fue similar a la poblacional: 55% mujeres y 45% hombres. La distribucion por especialidades fue 32% cirugia general, 21% cirugia colorectal, 22% cirugia oncologica y 25% otras. Las cirugias fueron electivas en 87% y emergencias en 13%. Se reportaron complicaciones en 3% de los casos y la mortalidad fue de 1%. Conclusion: A pesar de que solamente 14% de la poblacion general es de 65 anos o mas, la poblacion quirurgica tiene un 28% de casos en esa categoria de edad. Los pacientes de edad avanzada representan una porcion significativa del trabajo de los servicios de cirugia. Encontramos que cirugia general, cirugia colorectal y cirugia oncologica prestan 75% del total de los servicios quirurgicos.


Since being able to analyze procedural statistics has become so important in current medical practice, the Department of Surgery of the University of Puerto Rico established a database that collects patient and procedural information. The information collected by databases helps individual physicians make day-to-day decisions on patient care and also facilitates the development of epidemiological models (l).

Our Surgical Database is a confidential database of surgical procedures and their attendant patient-related details; it is compliant with the Health Insurance Portability and Accountability Act (HIPAA). This database contains basic demographic information for each registered patient along with clinical data pertaining to that patient's surgery. Our facility generates a vast amount of surgical information that can be used for epidemiological and procedural studies. In the past this information was not collected in a uniform manner so that it could be accessed for future research.

The purpose of this study was to report the information obtained on surgical procedures and to report, as well, the outcomes during the first year of the Surgical Database. In this first report, we have decided to address the age distribution and selected characteristics of the surgical population of the University of Puerto Rico-affiliated hospitals. This report will compare the outcomes of patients who were younger than 65 years of age with those of the patients who were 65 and older and also review the surgical services for which there is the greatest demand in our population.


We identified all the surgical cases entered, from January 1, 2013, to December 31, 2013, into the Surgical Database of the Department of Surgery of the University of Puerto Rico (UPR). This database collects patient and procedural information from the surgical services of the UPR-affiliated hospitals (University District Hospital; University Pediatric Hospital; UPR Carolina Hospital; Oncologic Hospital [Dr. I. Gonzalez Martinez], Pavia Hospital-colorectal service; and Auxilio Mutuo Hospital, the colorectal and oncologic services. The data were (and continue to be) obtained from the regular weekly reports, generated by residents, of the various surgical services at the participating hospitals. The pertinent details about the surgical procedures that were performed are extracted from the weekly reports and aggregated into the database. Personal identifiers are not included in the aggregated data. The database includes the following variables from each patient: age and gender, the surgical service used, outpatient/inpatient status, the diagnosis, the international classification of disease (ICD) code, the surgical procedure performed, the current procedural terminology (CPT) code, whether the surgery performed was an elective or emergency procedure, wound classification, and the outcome. For the purposes of the database, the variable "outcome" has 4 possible choices : uneventful, minor morbidity, major morbidity, and mortality. A minor morbidity is defined in the database as a superficial wound infection, superficial wound disruption, small seroma, small hematoma, or postoperative ileus. A major morbidity is any postoperative complication requiring medical/surgical attention and that is not included in the minor morbidity category.

The characteristics of the surgical population as a whole were evaluated during the 1-year study period. The group was subdivided into patients younger than 65 and those who were 65 and older, to evaluate whether the older patients responded differently to surgical management. All the variables studied were tabulated for the 2 subgroups and the values compared. Outcomes were also evaluated by gender.

Statistical analyses were performed with the software program SPSS, version 22.0 (Chicago, Illinois). Categorical variables were presented as frequencies and percentages. Quantitative variables were expressed as means plus or minus standard deviation. The study groups were compared using the chi-square test, Student s t-test, or ANOVA, whichever was appropriate. Differences between groups were considered to be statistically significant when the p-value was less than 0.05.

This database was reviewed and approved by the Institutional Review Board (IRB) of the University of Puerto Rico Medical Sciences Campus.


During the 1-year period of our study, the Surgical Database collected information on 5,263 surgical cases. The mean age of this group was 48 ([+ or -]23) years; the median age was 53 years. We found that 28% of the surgical population was 65 years of age or older and that the individuals with the highest rates of surgery were those in the 61- to 70-year-old age group (Figure 1). Regarding the gender distribution of the surgical population, it was found to be similar to that of the distribution of the general population: 55%, female, and 45%, male.

The highest demands for surgical services occurred in general surgery (32%), oncologic surgery (22%), and colorectal surgery (21%) (Table 1). Wound classification was reported as clean in 51.5% of the patients, clean-contaminated in 32.5%, contaminated in 8.6%, and dirty or infected in 5.6%. Our study indicated that 39% of the surgeries were performed on an outpatient basis. The majority of the cases were classified as elective (86.5%) and without complications (uneventful) (96.9%). Complications were reported in only 3% of the cases and mortality was reported in only 1%.

When the group was divided by age group, those who were younger than 65 years of age and those who were 65 or older, a few differences were found. A slightly higher mortality from surgical procedures was noted in patients belonging to the older group ( 1.0%), compared to the younger one (0.3%); this was statistically significant (p<0.05), as can be seen in Table 2. The percentage of older patients was higher in the oncologic surgery service (37%) and the vascular surgery service (56%) than it was in the general surgery service (25%) (Table l). When the mean ages (years) of the oncologic (58[+ or -]15) and vascular surgery patients (63+16) were compared to the mean age of the general surgery patients ( 50[+ or -]19), we found that the patients in the former 2 groups were significantly older than those in the latter (p<0.05).

Differences by gender are shown in Table 2, with males having a slightly higher major surgical morbidity (2% vs. 1%; p<0.05).


The median age of our clinical population was 53 years, while the median age of the general population of Puerto Rico is 37 years, according to the United States Census Bureau (2). Our study found that 28% of the surgical population was in the 65-and-over age group, meaning that this age group's presence in the surgical population is twice that of its presence in the general population (2). The United States and Puerto Rico are both experiencing major demographic shifts. In the coming decades, people aged 65 and over will make up an increasingly large percentage of the population (2-4). This shift is happening for 2 reasons: people are living longer, and many couples are choosing to have fewer children (decreasing birth rate). There is also the contribution consisting of baby boomers who are reaching their golden years. Older patients now represent a significant proportion of the surgical workload, with the greater delivery of care that this group requires (5-6). Elderly patients are vulnerable, especially in the postoperative period, because of the physiological changes of aging and this population's (generally) limited physiological reserves in terms of being able to tolerate the stress of a surgical procedure.

Despite the growth of the elderly population, most surgical training programs lack formalized geriatric education. It has been suggested that we should develop and implement a formalized geriatric surgery curriculum for general surgery residents (7-10). Geriatric patients have specific medical and social needs that surgeons must learn to take into consideration. Validated scales are currently available to evaluate preoperative variables predictive of poor surgical outcomes, which scales include the Hopkins Frailty Score (11), the Preoperative Comprehensive Geriatric Assessment (12-13), and the Aging Frailty Index (14). Through the use of these scales, surgeons can determine who is too frail for surgery.

Our study also found that 75% of the demand for surgical services occurs in the areas of general, oncologic, and colorectal surgery. Again, this is consistent with the literature reports showing these services to be the most used by elderly populations (15-16). In particular, cancer surgery is very frequent in the elderly (15-16). Nonetheless, this general surgery database does not collect data from the orthopedic, urology, or ophthalmology services, all of which are also known to be in high demand among the elderly.

Meanwhile, currently, 39% of our surgeries are performed on an outpatient basis, which is slightly lower than the average of 54%, which is reported for the United States (17).

Subdividing the group into those who are younger than 65 and those who are 65 years of age and older allowed us to compare how the variables in the database differ for the 2 age groups. Elderly patients have a slightly higher mortality rate from surgical procedures (1.0% vs. 0.3%), which is statistically significant (p<0.05). The oncologic (37%) and vascular (57%) surgery services have the highest percentages of elderly patients, similar to what has been reported in the literature (15,16,18).

Our study showed that we have low complication (3%) and mortality rates (l%). It has been reported that in the United States, the overall 30-day mortality after surgery is between 1.9 and 2.1%, and that surgical complications occur in 12% of the cases (19-20). However, as the number of elderly patients increases, we could face higher morbidity and mortality rates. As populations continue to age, health care providers must meet the challenge of providing appropriate surgical care for the elderly.

With regard to the study's limitations; it is important to realize that our database obtains information from the UPR-affiliated hospitals and from selected services of the participating private hospitals; therefore, our database does not represent the general population of PR. Nonetheless, this database will facilitate research into and about surgical outcomes and may be used to study the patterns of regional practices.


(1.) Murphy M, Alavi K, Maykel J. Working with existing databases. Clin Colon Rectal Surg 2013;26:5-11.

(2.) US Census Bureau. Statistical Abstract of the United States: 2012. 131st ed. Washington, DC: US Bureau of the Census; 2012. Available at: Url: publications/2011/ compendia/statab/ 131ed.html. Accessed July 6, 2014.

(3.) McVeigh TP, Al-Azawi D, O'Donoghue GT, Keri MJ. Assessing the impact of an aging population on complication rates and in-patient length of stay. Int J Surg 2013;11:872-875.

(4.) National Research Council. Aging and the Macroeconomy: Long-Term Implications of an Older Population. Washington, DC: The National Academies Press; 2012:1-4.

(5.) Edgar DW, Homer L, Phillips M, Gurfinkel R, Rea S, Wood FM. The influence of advancing age on quality of life and rate of recovery after treatment for burn. Burns 2013;39:1067-1072.

(6.) Badgwell B, Stanley J, Chang GJ, et al. Comprehensive geriatric assessment of risk factors associated with adverse outcomes and resource utilization in cancer patients undergoing abdominal surgery. J Surg Oncol 2013;108:182-186.

(7.) Barbas AS, HaneyJC, Henry BV, et al. Development and implementation of a formalized geriatric surgery curriculum for general surgery residents. Gerontol Geriatr Educ 2014;35:380-394.

(8.) Webb TP, Duthie E Jr. Geriatrics for surgeons: infusing life into an aging subject. J Surg Educ 2008;65:91-94.

(9.) Duane TM, Fan L. Bohannon A, et al. Geriatric education for surgical residents: identifying a major need. Am Surg 2011;77:826-831.

(10.) Petronovich J. Wade TJ, Denson K, Webb TP. Elderly surgical patients: are there gaps in residency education. J Surg Educ 2014;71:825-828.

(11.) Revenig LM, Canter DJ, Taylor MD, et al. Too frail for surgery? Initial results of a large multidisciplinary prospective study examining preoperative variables predictive of poor surgical outcomes. J Am Coll Surg 2013; 217:665-670.

(12.) Kim KI, Park KH, Koo KH, et al. Comprehensive geriatric assessment can predict postoperative morbidity and mortality in elderly patients undergoing elective surgery. Arch Gerontol Geriatr 2013;56:507-512.

(13.) Partridge JS, Harari D, Martin FC, Dhesi JK. The impact of pre-operative comprehensive geriatric assessment on postoperative outcomes in older patients undergoing scheduled surgery: a systematic review. Anesthesia 2014;69(Suppl1):8-16.

(14.) Farhat JS, Velanovich V, Falvo AJ, et al. Are the frail destined to fail? Frailty index as predictor of surgical morbidity and mortality in the elderly. J Trauma Acute Care Surg 2012;72:1526-1530.

(15.) Fontani A, Martellucci J Civitelli S, Tanzini G. Outcome of surgical treatment of colorectal cancer in the elderly. Updates Surg 2011;63:233-237.

(16.) Oksuzyan A, Jeune B, Juel K, et al. Changes in hospitalization and surgical procedures among the oldest-old: a follow-up study of the Danish 18951905 cohorts from ages 85 to 99 years. Age Ageing 2013;42:476-481.

(17.) Sheetz KH, Corona L, Cramm S, et al. Variation in ambulatory surgery utilization in Michigan. J Surg Res 2014; 189:255-261.

(18.) Karam J, Tsiouris A, Shepard A, et al. Simplified frailty index to predict adverse outcomes and mortality in vascular surgery patients. Ann Vase Surg 2013;27:904-908.

(19.) Reames BN, Krell RW, Campbell DA Jr, Dimick JB. A checklist-based intervention to improve surgical outcome in Michigan: evaluation of the Keystone surgery program. JAMA Surg 2015;150:208-215.

(20.) Etzioni DA, Wasif N, Dueck AC, et al. Association of hospital participation in surgical outcomes monitoring program with inpatient complications and mortality. JAMA 2015;313:505-511.

Norma I. Cruz, MD, Elvis Santiago, MS, Fernando Rivera, BS

Department of Surgery, School of Medicine, University of Puerto Rico

The authors have no conflict of interest to disclose.

Address correspondence to: Norma I. Cruz, MD, Department of Surgery, School of Medicine, University of Puerto Rico, P.O. Box 365067, San Juan, PR 00936-5067. Email:
Table 1. Characteristics of the surgical population of the
University of Puerto Rico-affiliated hospitals and comparisons
by age (December 1, 2013-December 31, 2013) (n = 5,263).

Variables               Frequency      Age (years)        P value
(n = 5263)              n (%)          mean [+ or -] SD   (A)

Gender **
Male                    2381 (45%)     46 [+ or -] 25     <0.05
Female                  2870 (55%)     50 [+ or -] 22

Surgery services ***
Cardiothoracic          286 (5.4%)     53 [+ or -] 22     <0.05
Colorectal              1126 (21.4%)   55 [+ or -] 17
General                 1655 (31.5%)   50 [+ or -] 19
Oncologic               1151 (21.9%)   58 [+ or -] 15
Pediatric               625 (11.9%)    5 [+ or -] 6
Plastic                 140 (2.7%)     48 [+ or -] 17
Vascular                217 (4.1%)     63 [+ or -] 16
Hepatobiliary           60 (1.1%)      62 [+ or -] 14

Admission status
Inpatient               3186 (60.6%)   47 [+ or -] 25     <0.05
Outpatient              2072 (39.4%)   50 [+ or -] 20

Wound classification
  ([double dagger])
Clean                   2673 (51.5%)   49 [+ or -] 23     <0.05
Clean-contaminated      1686 (32.5%)   46 [+ or -] 24
Contaminated            448 (8.6%)     45 [+ or -] 24
Dirty/infected          289 (5.6%)     51 [+ or -] 22
Other                   85 (1.6%)      57 [+ or -] 15
N/A                     6 (0.11%)      45 [+ or -] 21

Outcome ([dagger])
Uneventful              2860 (96.8%)   48 [+ or -] 23     0.01
Minor morbidity         39 (1.3%)      50 [+ or -] 22
Major Morbidity         42 (1.4%)      39 [+ or -] 29
Mortality               14 (0.5%)      59 [+ or -] 30

Surgery type
Elective                1460 (86.5%)   50 [+ or -] 23     <0.05
Emergency               227 (13.5%)    35 [+ or -] 26

                                  Age (n, %) *

                                           [greater than or
Variables               <65 years          equal to] 65 years   P value
(n = 5263)              (n = 3,797, 72%)   (n = 1,460, 28%)     (B)

Gender **
Male                    1731 (73%)         650 (27%)            0.52
Female                  2059 (72%)         805 (28%)

Surgery services ***
Cardiothoracic          200 (70%)          86 (30%)             0.37
Colorectal              757 (67%)          367 (33%)            <0.05
General                 1249 (75%)         406 (25%)            <0.05
Oncologic               720 (63%)          430 (37%)            <0.05
Pediatric               625 (100%)         0                    --
Plastic                 112 (81%)          27 (19%)             <0.05
Vascular                94 (44%)           122 (56%)            <0.05
Hepatobiliary           38 (64%)           21 (36%)             0.18

Admission status
Inpatient               2290 (72%)         891 (28%)            0.59
Outpatient              1505 (73%)         566 (27%)

Wound classification
  ([double dagger])
Clean                   1888 (71%)         783 (29%)            <0.05
Clean-contaminated      1243 (74%)         441 (26%)            0.11
Contaminated            343 (77%)          104 (23%)            <0.05
Dirty/infected          210 (73%)          78 (27%)             0.83
Other                   60 (71%)           25 (29%)             0.71
N/A                     6 (100%)           0                    --

Outcome ([dagger])
Uneventful              2090 (73%)         764 (27%)            0.42
Minor morbidity         27 (69%)           12 (31%)             0.58
Major Morbidity         33 (79%)           9 (21%)              0.42
Mortality               6 (43%)            8 (57%)              <0.05

Surgery type
Elective                1029 (71%)         425 (29%)            <0.05
Emergency               192 (85%)          35 (15%)

(A) Student's t-test or ANOVA for p-value. (B) Chi-square test for
p-value. * The comparisons are not registered in all the surgeries;
** Registered in 5251 surgeries; *** Registered in 5260 surgeries;
([section]) Registered in 5258 surgeries; ([double dagger]) Not
registered in 76 surgeries; ([dagger]) Registered in 2955
surgeries; ([dagger][dagger]) Registered in 1687 surgeries. When
comparing the 2 age groups (<65 vs. [greater than or equal to] 65),
the different surgical services, wound classifications, and
outcomes are treated as different variables (yes/no), and this is
why each one has one p-value.

Table 2. Postoperative mortality and morbidity (by age and
gender) of the surgical population of the University of Puerto
Rico-affiliated hospitals (December 1, 2013-December 31, 2013)
(n = ?).

                        Age Group (n, %)

                                 [greater than
                                 or equal to]
                  <65 years      65 years
Outcome           n = 2,156      n = 793         P Value

Mortality         6 (0.3%)       8 (1.0%)        <0.05
Major morbidity   33 (1.5%)      9 (1.1%)        0.42
Minor morbidity   27 (1.3%)      12 (15%)        0.58
Uneventful        2090 (96.9%)   764 (96.3%)     0.42

                        Gender (n, %)

                  Male           Female
Outcome           n = 1333       n = 1611       P Value

Mortality         7 (0.5%)       6 (0.4%)       0.59
Major morbidity   26 (2.0%)      16(1.0%)       <0.05
Minor morbidity   23 (1.7%)      16 (1.0%)      0.11
Uneventful        1277 (95.8%)   1573 (97.6%)   <0.05

Chi-square test used for p-value. Outcome by age was
registered for 2949 cases and by gender for 2944 cases

Figure 1. Age distribution of the surgical population of the
University of Puerto Rico-affiliated hospitals (n = 5,263)

<1       4.2
1-9      5.6
10-19    5.5
20-30    6.7
31-40    9.8
41-50   14.3
51-60   18.2
61-70   19.1
71-80   12.4
>91      0.25

Note: Table made from bar graph.
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Author:Cruz, Norma I.; Santiago, Elvis; Rivera, Fernando
Publication:Puerto Rico Health Sciences Journal
Date:Mar 1, 2016
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