Connor Zale, Thomas J. VanderMeer M.D. and Laura Fitzgerald
Department of Research at Robert Packer Hospital
1 Guthrie Square, Sayre, PA 18840
This project was designed to analyze if there is a disparity in access to surgical care due to socioeconomic status for patients in the Twin Tiers region. Elective and emergent cholecystectomies were used as indicators for access to surgical care. Socioeconomic status was determined by insurance status, education, and income. Healthcare Association of New York (HANYS) was accessed in order to obtain patient records that have undergone a cholecystectomy between January 2007 and June 2014.
The report collected 15,767 patient records and elective cases (11,165, 70.8%) outnumbered emergent cases (4,601, 29.2%). Laparoscopic cases (15,299, 97.04%) were the preferred procedure compared to open procedures (467, 2.96%). Cholecystectomy rates per capita by zip code were modeled with socioeconomic census data and trend was analyzed using non-parametric regression.
A higher elective cholecystectomies rate per capita was found to occur in middle income households and also in communities with a 15-18 percent in poverty. Elective cholecystectomy rate per capita was found to decrease dramatically when the percent of the community with a high school degree was greater than 90 percent. The rate of emergent cholecystectomies per capita was uniform across all socioeconomic indicators. Future research will investigate what community resources may be available to account for the variable rate of elective cholecystectomies. The role of urban and rural setting will also be investigated in the future to determine the effect on cholecystectomy case type.
Diseases of the gallbladder are the most commonly treated of all the digestive system diseases. The two primary types of gallbladder disease are gallstones, cholelithiasis, and gallbladder cancer1. Gallstones affect large portion of Americans and treatment of gallstones has become a substantial portion of the national healthcare cost. It has been estimated that over 20 million Americans suffer from gallstones. Gallbladder disease has been approximated to consume 6.2 billion dollars annually and it has increased over 20% over the last 3 decades2.
Due to the enormous amount spent on cholecystectomies each year, this surgical procedure was selected to model patients’ access to care. It was hypothesized that patients with higher socioeconomic status will undergo the procedure electively and patients from a lower socioeconomic status will delay the procedure. This may cause a higher proportion of emergent cholecystectomies for patients of lower socioeconomic status.
The gall bladder is a small organ that lies underneath the liver and it is connected to the duodenum by the common bile duct. The role of the gallbladder is to store bile which is produced by the liver and the bile is stored until it is released into the duodenum in order to digest fats. Bile is composed of bile salts, bilirubin and cholesterol. Gallstones can be composed of hardened cholesterol or complexes of calcium salts, bilirubin, copper, cholesterol and protein3.
There are several risk factors for an increased incidence of gallstones. The primary risk factors are age, gender, number of pregnancies, BMI, oral contraceptives, estrogen therapy, family history and genetics. It has been noted that increased age results in an increased risk for gallstones and cholecystitis. Females are 2.4 times more likely to have gallbladder issues than men due to hormones, estrogen and progesterone. Obesity has also been determined to be a risk factor for gallstone formation8.
The presence of gallstones may not cause symptoms until complications arise such as, inflammation, infection and obstruction of the common bile duct. Patients that experience symptoms from gallstones commonly state the presence of biliary colic which is a visceral pain that is believed to be caused by the obstruction of the cystic duct. Patients can be treated for gallstones with surgical and non-surgical interventions. An oral dose of bile acids can assist in the treatment of gallstones by medical dissolution therapy. The common surgical treatments are open or laparoscopic cholecystectomy and open or laparoscopic cholecystostomy. A cholecystectomy is the complete removal of a gallbladder and primarily is completed as laparoscopic procedure. A cholecystostomy is the process of forming an opening in the gallbladder and a tube is placed inside the gallbladder for drainage. A cholecystostomy is usually performed when there are preexisting issues that to do not make a cholecystectomy possible4.
The Society of American Gastrointestinal and Endoscopic Surgeons provide guidelines for laparoscopic operations on the gallbladder and biliary tree, which allow procedures for symptomatic cholelithiasis, biliary dyskinesia, acute cholecystitis and complications related to the common bile duct stones5. A cholecystectomy can be determined to be elective in most cases when the complications of gallstones due not pose an immediate threat to the patient. A cholecystectomy can be advised to the patient when biliary colic is negatively affecting the patient and the patient does not have any major issues in order to undergo surgery6. Other indications for a prophylactic cholecystectomy include calculi greater than 3 cm in diameter for individuals from regions with a higher prevalence of gallbladder cancer, a chronically obliterated cystic duct, a nonfunctioning gallbladder, a calcified gallbladder, a gallbladder polyp larger than 10 mm and growing in size, gallbladder trauma or an anomalous junction of the pancreatic and biliary ducts7.
Electronic Medical Records were accessed using Healthcare Association of New York State database (HANYS). Records were collected for patients that underwent an open or laparoscopic cholecystectomy between January 2007 and June 2014. Age, Gender, Zip Code, Insurance Status, Procedure and Case type (elective or emergent) was obtained for analysis. Emergent cholecystectomies were identified by an emergency room code that was attached to the case type within the report. Pregnant women and children were excluded from this study. Patient zip code was paired to U.S. Census data for median income, percentage of the population in poverty and percentage of population with at least a high school level degree.
T-tests were performed for age by case type for each gender separately. Insurance status for emergent cases was compared to institutional data for all patients at Robert Packer Hospital and Corning Hospital. Scatter plots were constructed using cholecystectomy rates and socioeconomic indicators to determine if there was a trend. The trend for each graph was created using local polynomial regression fitting (LOESS). Statistical tests were conducted using R software. Figures were created with R software and Microsoft Excel.
This project was reviewed and approved by Guthrie Institutional Review Board prior to data collection. This project was determined to be a minimal risk study because the only patient identifier, B number, was removed prior to statistical analysis. A waiver for patient consent was obtained for this study since it was a retrospective chart review by design.
The HANYS report collected 15,767 total cholecystectomy cases for patients that reside within Guthrie’s primary and secondary service area (Figure 1). There were 11,165 elective cases (70.8%) and 4,601 emergent cases (29.2%) (Figure 2). One case was identified as unknown case type and this was excluded from case type analysis. The elective cases included 11,045 laparoscopic procedures and 120 open procedures. Emergent cases included 4,254 laparoscopic procedures and 347 open procedures. There were 15,299 laparoscopic procedures (97%) and 467 open procedures (3%) in total.
The number of elective cholecystectomies by gender was 8,076 female (72.3%) and 3,088 male (27.7%). There were 2,820 females (61.3%) and 1,781 males (38.7%) that underwent an emergent cholecystectomy (Figure 2). T-tests were performed for age for elective and emergent cases by gender. There was a significant difference between the age of elective and emergent cases for men and women (p<2.2E-16 and p<2.2E-16) (Table 1).
The insurance statuses for emergent and elective cases were compared to determine disparities in access to care. The most common insurance plans were Medicare and Blue Cross for elective and emergent cholecystectomies. Medicare was the top insurance plan for emergent procedure and Blue Cross was the most common insurance plan for elective procedures. Medicaid is the third most frequent insurance plan for the emergent cases but Commercial plans is the third most frequent for elective cases. (Table 2 and Figure 3).
Census data was paired to the patient’s Zip Code information to determine rates of cholecystectomies per capita (Tables 3 and 4). The Zip Codes with greater than thirty patients for emergent procedure and greater than 90 patients for elective procedures were utilized for these models. This resulted in 34 top Zip Codes for elective case type and 35 top Zip Codes for emergent case types. Scatter plots were constructed with the cholecystectomy rate for elective and emergent case types and socioeconomic status indicators (Figures 4, 5 and 6). The rate of emergent cholecystectomies was primarily uniform across all socioeconomic indicators. The trend for highest rates of elective cholecystectomies occurred in middle class communities with $40,000-50,000 median household income. A higher elective cholecystectomy rate was also determined in communities with moderate percentage in poverty (15-18%) out of the studied Zip Codes. The rate of elective cholecystectomies per capita dramatically dropped in communities that had more than 90% of individuals with a high school degree.
This project was unable to present a strong relationship between socioeconomic status and rates of emergent and elective cholecystectomies. Several aspects of this project can be identified as limitations for this study. Pairing secondary census data to primary zip code data may not provide an accurate representation for the specific patient’s socioeconomic status.
This study determined that the incidence for cholecystectomies from the twin tiers region is comparable to National average for males and females. The elective cases outnumber emergent cases 2.4 to 1. This may be due attributed to each surgeon’s preference to perform a cholecystectomy when gallstones are asymptomatic. Only 20% of patients with gallstones will become symptomatic and will present with cholecystitis. The higher percentage of elective procedures can be due to prophylactic removal or to early treatment of initial symptoms of cholecystitis. Laparoscopic procedures (97%) far outweighed open procedures (3%). Laparoscopic procedures are the preferred surgical option because the recovery time and infection rates are lower than open procedures.
There was a significant difference determined between ages of patients that have undergone an elective or emergent procedure by gender. The emergent cholecystectomies had a higher average age for both genders than emergent cholecystectomies. The p- value should be noted to be extremely low due to the large sample size for both groups. While this result is significant, the average ages only differ by about 6-7 years for men and women between elective and emergent procedures.
The insurance status did show a difference in insurance types between patients that have undergone an elective or emergent cholecystectomy. Many more patients belonged to a Medicare insurance plan that received an emergent cholecystectomy than elective cholecystectomy. This information also supports the evidence that the patient population for emergent cholecystectomies had a higher average age than the patient population receiving elective cholecystectomies. Emergent cholecystectomy patients may also have a lower socioeconomic status than elective cholecystectomy patients because a higher proportion of patients belonged to a self-pay plan and a lower percentage of patients belonged to commercial insurance plans when compared to elective cholecystectomy patients.
Secondary census data had to be applied to HANYS patient data in order to study cholecystectomy rates per capita by Zip Code for any trends across income, education level and poverty level. Findings revealed higher elective cholecystectomy rates per capita were found for communities with middle level median household incomes and communities with a poverty level between 15 and 18 percent. Elective cholecystectomy rates dropped for communities that had a high school graduation rate greater than 90 percent. It is indeterminate at this point why these specific communities presented these unique trends across the socioeconomic indicators.
Results from this study may provide healthcare organizations with preliminary list of hot spot communities for emergent and elective cholecystectomies. This may then allow organizations with necessary information to target these communities with outreach for nutrition and healthy lifestyle initiatives in order to decrease patients’ risk factors for gallstones and cholecystitis. Healthcare organizations in these geographical areas can also sponsor information sessions for primary care providers in these communities to identify and manage high risk patients in these hot spot communities.
Future studies will compare the resources available within these various communities to determine why the rate of elective cholecystectomies is higher in middle level income communities and how some communities have lower elective procedures when there is a higher high school graduation rate. Future studies can also investigate cholecystectomy rates per capita and socioeconomic status between urban and rural communities. A national healthcare database can be utilized to obtain a comprehensive list of cholecystectomies in these regions in order to study if there is a trend for access to surgical care and type of residence. Studies will also have to include a larger patient population to study a larger geographical area.
The authors thank Guthrie Marketing Department for compiling the data for this study; Guthrie Institutional Review Board for approving and overseeing this project; Guthrie Healthcare for supporting this project; and faculty and staff at Robert Packer Hospital for their assistance.
1. Digestive Diseases and Gallbladder Disease. New York Presbyterian.
2. Stinton, Laura M. and Eldon A. Shaffer. Epidemiology of Gallbladder Disease: Cholelithiasis and Cancer. Gut and Liver. Apr 2012, 6(2) 172-187.
T-tests were performed for age by case type with each gender. There was a significant difference between age and case types by gender.
Table 2: Insurance Status and Cholecystectomy Case Type
The insurance status for patients that have undergone an elective or emergent procedure and reside in the Twin Tiers region is displayed above. Medicare and Blue Cross were the top insurance plans that patients were enrolled.
Table 3: Elective Cholecystectomy Rate per Capita by Zip Code
The elective cholecystectomy rate per capita, population and socioeconomic data is displayed above. The population and socioeconomic data was obtained from U.S. Census 2010 information.
Table 4: Emergent Cholecystectomy Rate per Capita by Zip Code
The emergent cholecystectomy rate per capita, population and socioeconomic data is displayed above. The population and socioeconomic data was obtained from U.S. Census 2010 information.
The map above displays the primary (green) and secondary (red) service area for Guthrie Healthcare. Patients that have undergone a cholecystectomy and reside in the region were included in the HANYS report.
Figure 2: Cholecystectomies by Case Type and Procedure
The figure above displays the number and procedure type for elective and emergent cholecystectomies performed for patients residing in the Twin Tiers Region.
Figure 3: Insurance Status of Emergent and Elective Cholecystectomies
The insurance status for emergent cholecystectomies and elective cholecystectomies is displayed above. The majority of patients were insured by Blue Cross or Medicare in both groups. Medicaid was the third most popular insurance type for patients that underwent an emergent cholecystectomy. Medicaid was the fourth most common insurance type for elective cholecystectomies.
Figure 4: Elective and Emergent Cholecystectomy Rates per Capita and Median Income by Zip Code
The figure above displays the cholecystectomy rate per capita and median income by Zip Code. Elective procedures are displayed in black and emergent procedures are displayed in red. A higher cholecystectomy rate trend occurs between 40,000 and 50,000 for elective procedures. The trend for emergent procedures is uniform across all median household incomes.
Figure 5: Elective and Emergent Cholecystectomy Rates per Capita and Percentage Graduated High School by Zip Code
The figure above displays the cholecystectomy rate per capita and percentage of the population that have graduated high school by Zip Code. Elective procedures are displayed in black and emergent procedures are displayed in red. The trend for elective cholecystectomy rates per capita drops after the percentage of the population with a high school degree passes 90 percent. The trend for emergent procedures is uniform across all graduation percentages.
Figure 6: Elective and Emergent Cholecystectomy Rates per Capita and Percentage in Poverty by Zip Code
The figure above displays the cholecystectomy rate per capita and percentage of the population in poverty by Zip Code. Elective procedures are displayed in black and emergent procedures are displayed in red. The trend for elective cholecystectomy rates is greatest when the poverty level is between 15 and 18 percent.