Management of asymptomatic gallstones in the diabetic patient. A decision analysis

Cholecystectomy for asymptomatic gallstones: Markov decision tree analysis

Gallstones are a common public health problem, especially in developed countries. There are an increasing number of patients who are diagnosed with gallstones due to increasing awareness and liberal use of imaging, with 22.6%-80% of gallstone patients being asymptomatic at the time of diagnosis. Despite being asymptomatic, this group of patients are still at life-long risk of developing symptoms and complications such as acute cholangitis and acute biliary pancreatitis. Hence, while early prophylactic cholecystectomy may have some benefits in selected groups of patients, the current standard practice is to recommend cholecystectomy only after symptoms or complications occur. After reviewing the current evidence about the natural course of asymptomatic gallstones, complications of cholecystectomy, quality of life outcomes, and economic outcomes, we recommend that the option of cholecystectomy should be discussed with all asymptomatic gallstone patients. Disclosure of material information is essential for patients to make an informed choice for prophylactic cholecystectomy. It is for the patient to decide on watchful waiting or prophylactic cholecystectomy, and not for the medical community to make a blanket policy of watchful waiting for asymptomatic gallstone patients. For patients with high-risk profiles, it is clinically justifiable to advocate cholecystectomy to minimize the likelihood of morbidity due to complications.

Frequency of cholecystectomy and associated sociodemographic and clinical risk factors in the ELSA-Brasil study

CONTEXT AND OBJECTIVE

There are few data in the literature on the frequency of cholecystectomy in Brazil. The frequency of cholecystectomy and associated risk factors were evaluated in the Brazilian Longitudinal Study of Adult Health (ELSA-Brasil).

DESIGN AND SETTING

Cross-sectional study using baseline data on 5061 participants in São Paulo.

METHODS

The frequency of cholecystectomy and associated risk factors were evaluated over the first two years of follow-up of the study and over the course of life. A multivariate regression analysis was presented: odds ratio (OR) and 95% confidence interval (95% CI).

RESULTS

A total of 4716 individuals (93.2%) with information about cholecystectomy were included. After two years of follow-up, 56 had undergone surgery (1.2%: 1.7% of the women; 0.6% of the men). A total of 188 participants underwent cholecystectomy during their lifetime. The risk factors associated with surgery after the two-year follow-up period were female sex (OR, 2.85; 95% CI, 1.53-5.32), indigenous ethnicity (OR, 2.1; 95% CI, 2.28-15.85) and body mass index (BMI) (OR, 1.10; 95% CI, 1.01-1.19 per 1 kg/m2 increase). The risk factors associated over the lifetime were age (OR, 1.03; 95% CI, 1.02-1.05 per one year increase), diabetes (OR, 1.92; 95% CI, 1.34-2.76) and previous bariatric surgery (OR, 5.37; 95% CI, 1.53-18.82). No association was found with parity or fertile age.

CONCLUSION

Female sex and high BMI remained as associated risk factors while parity and fertile age lost significance. New factors such as bariatric surgery and indigenous ethnicity have gained importance in this country.

Evidence-based current surgical practice: calculous gallbladder disease

BACKGROUND

Gallbladder disease is common and, if managed incorrectly, can lead to high rates of morbidity, mortality, and extraneous costs. The most common complications of gallstones include biliary colic, acute cholecystitis, common bile duct stones, and gallstone pancreatitis. Ultrasound is the initial imaging modality of choice. Additional diagnostic and therapeutic studies including computed tomography, magnetic resonance imaging, magnetic resonance cholangiopancreatography, endoscopic ultrasound, and endoscopic retrograde cholangiopancreatography are not routinely required but may play a role in specific situations.

DISCUSSION

Biliary colic and acute cholecystitis are best treated with early laparoscopic cholecystectomy. Patients with common bile duct stones should be managed with cholecystectomy, either after or concurrent with endoscopic or surgical relief of obstruction and clearance of stones from the bile duct. Mild gallstone pancreatitis should be treated with cholecystectomy during the initial hospitalization to prevent recurrence. Emerging techniques for cholecystectomy include single-incision laparoscopic surgery and natural orifice transluminal endoscopic surgery. Early results in highly selected patients demonstrate the safety of these techniques. The management of complications of the gallbladder should be timely and evidence-based, and choice of procedures, particularly for common bile duct stones, is largely influenced by facility and surgeon factors.

Surgical treatment of gallstones

Currently there is no evidence for prophylactic cholecystectomy to prevent gallstone formation (grade B). Cholecystectomy cannot be recommended for any group of patients having asymptomatic gallstones except in those undergoing major upper abdominal surgery for other pathologies (grade B). Laparoscopic cholecystectomy is the preferred treatment for all patient groups with symptomatic gallstones (grade B). Patients with gallstones along with common bile duct stones treated by endoscopic sphincterotomy should undergo cholecystectomy (grade A). Laparoscopic cholecystectomy with laparoscopic common bile duct exploration or with intraoperative endoscopic sphincterotomy is the preferred treatment for obstructive jaundice caused by common bile duct stones, when the expertise and infrastructure are available (grade B).

Prophylactic cholecystectomy is not indicated following renal transplantation

BACKGROUND

The appropriate management of gallstones in patients undergoing renal transplantation is controversial. Screening for gallstones and subsequent prophylactic cholecystectomy has been recommended by some authors for kidney transplant candidates. Our program does not practice routine pretransplant screening for gallstones, and we reviewed our data to determine the outcome of our management approach.

METHODS

We reviewed the records of the 1,364 currently followed patients who have undergone kidney transplant at our institution since 1985 in order to evaluate the morbidity and mortality of biliary disease in the post-transplant period. We attempted to contact all patients by telephone or mail survey for the presence of biliary tract disease or operations.

RESULTS

Six hundred and sixty-two patients were fully evaluated. Fifty-two (7.85%) required cholecystectomy for stone disease. Seven patients underwent incidental cholecystectomy during other operations, 2 patients developed acalculus cholecystitis, and 14 patients with asymptomatic cholelithiasis are being followed up. Surgical indications included 38 biliary colic, 9 acute cholcystitis, 3 gallstone pancreatitis, and 2 patients who were asymptomatic. Fifty-two patients underwent 30 laparoscopic cholecystectomies, 20 open cholecystectomies, and 2 conversions. Surgery occurred from 7 days to 9.6 years following transplantation. Overall, the median hospital stay (no postoperative stay) was 4 days (range 1 to 57). Patients undergoing laparoscopy had a median stay of 2 days compared with 7 days for those undergoing an open procedure. Complications were seen in 6 patients (11.5%) with no morbidity and no graft loss. The 1-, 2-, and 5-year graft survival was 98%, 96%, and 85%, respectively, in patients undergoing cholecystectomy.

CONCLUSIONS

Transplant patients are not at an increased risk for developing biliary tract disease compared with nontransplant patients. Gallstone disease does not have a negative impact on graft survival. Treatment of gallstones has a low risk and does not represent an increased risk of complications in patients following renal transplantation.

Diabetes and the hepatobiliary system

Diabetes mellitus can lead to metabolic changes that alter normal hepatic and biliary function and structure. These alterations in hepatic and biliary function and structure are usually benign, but in certain situations lead to significant, disabling disease. This article reviews the hepatic and biliary complications of diabetes, with emphasis on epidemiology, diagnosis, and management, as well as the glucose intolerance seen in liver disease.

Primer on medical decision analysis: Part 4--Analyzing the model and interpreting the results

This paper is the fourth of a five-part series that describes the principles of construction and evaluation of valid decision models. In this review, the authors describe the key principles of detecting and eliminating structural and programming errors in decision trees (debugging). In addition, they offer guidelines to facilitate the interpretation of analytic results of decision models.

Decision analysis in endocrinology and metabolism

Decision analysis is a powerful tool for synthesizing and analyzing clinical decisions in the practice of endocrinology and metabolism. The technique involves defining strategies for comparison, choosing a time horizon, constructing a decision tree and model, selecting outcomes and assigning probabilities, taking into account the value of time, calculating the net clinical and cost outcomes, and performing sensitivity analysis. This technique and its utility for different populations and changing health care settings are illustrated for the decision of screening for mild thyroid failure with a thyroid-stimulating hormone assay at the periodic health examination. The strengths and limitations of decision analysis and future applications in endocrinology and metabolism are explored.

Prevalence of gallbladder disease in diabetes mellitus

A study was undertaken to compare the prevalence of gallstone disease (gallstones observed on ultrasound or history of cholecystectomy) in 308 diabetics and 318 controls. There was a higher prevalence of gallstone disease (GSD) in diabetics (32.7%) compared to controls (20.8%; P < 0.001 chi-squared test). However, when gender was taken into account, the difference was only significant in females (diabetics 41.8% versus controls 23.1%; P < 0.001). Analysis by type of diabetes revealed that subjects with non-insulin-dependent diabetes mellitus (NIDDM) had a higher prevalence of GSD than controls for both genders: males-controls 18.1%, NIDDM 33.3% (P < 0.05), IDDM 15.6% ns; females-controls 23.1%, NIDDM 48.6% (P < 0.001), IDDM 36.3% (P < 0.05). On univariate analysis the following risk factors were associated with gallstones (P < 0.1): increased age, body mass index (BMI), triglycerides, LDL cholesterol, decreased HDL cholesterol, alcohol intake, family history of GSD, and female parity > 3. Using stepwise multiple, logistic regression, the following variables were identified as independently predictive of gallstones for each gender/diabetic combination: Males-NIDDM (N = 54), increased age, and decreased HDL; IDDM (N = 90), age and family history; Females-NIDDM (N = 74), increased age, diabetes, increased BMI, and decreased alcohol; IDDM (N = 91), increased BMI, age, decreased alcohol and family history. The proportion of subjects who underwent cholecystectomy was higher in females (46.7%) compared to males (21.7%; P < 0.01) but there were no differences between diabetics and controls in either sex. In conclusion, there was a higher prevalence of GSD in diabetics compared to controls. However, GSD is multifactorial and only in NIDDM females was diabetes an independent risk factor. The proportion of diabetics and controls with GSD who underwent cholecystectomy was equivalent.

Decision analysis in surgery

BACKGROUND

The technique of decision analysis is often applied to clinical policy and economic issues in surgery. Because surgeons may be unfamiliar with such work, this article catalogues decision analysis studies in the surgical specialties.

METHODS

We reviewed the medical literature (1966 to 1994) to identify surgical decision analysis studies and to assess trends over time. Each article was categorized according to the type of journal (surgical, other clinical, or technical) in which it was published and content, including surgical specialty, clinical topic, article focus (individual patient decision making, clinical policy, or cost-effectiveness), and primary findings.

RESULTS

Publication rates of surgical decision analysis have increased dramatically over time. Of the 86 total studies only six were published before 1980. In contrast, 44 studies appeared between 1990 and 1994. Although 77% were published in nonsurgical journals, decision analyses have begun to appear more regularly in surgical forums. Studies addressing all of the surgical specialties were found, although more than one half addressed topics in general surgery (34%) or cardiothoracic surgery (22%). The most frequent topics were gallstones (11 articles), head and neck cancer (five articles), coronary artery disease (four articles), and cerebral arteriovenous malformations (four articles). Articles focusing on clinical policy (i.e., those assessing surgical efficacy for broad groups of patients) now account for large majority of published decision analyses.

CONCLUSIONS

The use of decision analysis in surgery is growing steadily. Because decision analysis is being used to influence clinical policy, it is important for surgeons to be aware of these studies and to be able to review them critically.

Changing indications for laparoscopic cholecystectomy. Stones without symptoms and symptoms without stones

In less than a decade, laparoscopic methods have dramatically improved the safety and convenience of cholecystectomy. As a result, the number of cholecystectomies performed nationwide has increased significantly. Whether this increase is a reflection of any major change in operative indications is unclear; the actual answer may vary from community to community. Silent gallstones continue to represent a sometimes contentious therapeutic dilemma. Because their natural history is unlikely to have changed, the management guidelines previously established for open cholecystectomy continue to have relevance today. Thus, it can be agreed that the majority of patients with silent gallstones do not require a cholecystectomy. The changing risk-benefit ratio suggests that some liberalization of these guidelines may now be in order. Already a number of transplantation surgeons have begun to recommend pretransplant cholecystectomy for asymptomatic patients who are found to have gallstones during screening. Available evidence also appears to support the use of pre-emptive laparoscopic cholecystectomy for other indications such as in selected women of childbearing age, young children, and patients with very large gallstones. The problem of silent gallstones in diabetics continues to be more enigmatic, but some complicated diabetics are probably best managed with operation. Other patient groups who are at high risk of having adverse outcomes from expectant management will be more precisely identified by future research efforts. Laparoscopic cholecystectomy should also be helpful in patients with various forms of acalculous biliary disease. However, special caution is advisable in approaching chronic acalculous cholecystitis until more specific and reproducible diagnostic methods are further validated.

Life expectancy biases in clinical decision modeling

Clinical decision models often rely upon survival models predicated on disease-specific hazard functions combined with baseline hazard functions obtained from standard life tables. Two biases may arise in such a modeling process. First, life expectancy estimates may be biased even if estimates of survival probabilities are unbiased (misestimation bias). In simulation studies, the authors discovered that the magnitude of misestimation bias is larger as life expectancy increases, sample size decreases, and censoring percentage increases. In the context of a simple decision analysis, they found that imbalances in the sample sizes for the data used to estimate the parameters among different strategies resulted in non-optimal decisions in the long run. The second bias stems from misspecification of the survival model itself (misspecification bias). Using a simple cost-effectiveness model, the authors found that life expectancies and incremental cost-effectiveness ratios differed depending on whether an excess-mortality or a proportional-hazards model was specified. In addition, a predictable pattern was observed for these two survival models when extrapolated to other age and gender groups.

Natural history of gallstones in non-insulin-dependent diabetes mellitus. A prospective 5-year follow-up

This prospective study was undertaken to assess the natural history of gallstones in patients with non-insulin-dependent diabetes. Four hundred forty outpatients with diabetes mellitus were studied; 81 of these had gallstones diagnosed by ultrasound. On the basis of the information they gave, they were divided into two groups: A, asymptomatic; and B, symptomatic (previous episode(s) of biliary pain) at recruitment. Five years after diagnosis, the patients were recalled and questioned about their symptoms. Three of 81 could not be traced and eight had died from diseases not related to gallstones. Seventy were finally evaluated, 47 belonging to group A, 23 to group B. The cumulative percentage of initially asymptomatic patients who presented with biliary pain or complications during the follow-up was 14.9% (4.2% for complications). Of group A patients, 17% underwent cholecystectomy (one prophylactic, six elective and two emergency). One patient (2.1%) died after operation of obstructive jaundice. Of group B patients, 47.8% had biliary symptoms or complications (8.7% cholecystitis); 21.7% were operated (17.4% elective, 4.3% emergency cholecystectomy). Since few patients with asymptomatic gallstones and non-insulin-dependent diabetes mellitus develop pain or complications over time, prophylactic cholecystectomy is probably not advisable.

Gallbladder stones--dissolve, blast, or extract? Laparoscopic cholecystectomy versus 'the rest'

This article reviews selected aspects of the non-surgical/minimally invasive treatments of gallbladder stones (GBS) and discusses briefly the residual role of these treatments in the era of laparoscopic cholecystectomy. In patients with specific, gallstone-related symptoms who wish to retain their 'functioning' gallbladders, there are at least six different management options. They range from rapid but invasive to slow but safe: i) the rotary lithotrite; ii) percutaneous cholecystolithotomy; iii) percutaneous transhepatic or iv) endoscopic retrograde cannulation of the gallbladder followed by instillation (manual or pump-assisted) of contact solvents; v) extracorporeal shock-wave lithotripsy + adjuvant bile acids and; vi) oral bile acids alone. The recommended investigation sequence is i) ultrasound (to diagnose the presence of GBS), followed by ii) oral cholecystography (to assess cystic duct patency, gallbladder anatomy and GBS size, number, lucency, buoyancy, and contour), and iii) regional computed tomography scanning of the gallbladder (to predict stone composition and dissolvability and to plan routes of access to the gallbladder). The decision-making steps are i) choice of some form of active treatment versus no treatment (other than observation); ii) in those with specific symptoms and a patent cystic duct who opt for active treatment, to choose between removing versus retaining the gallbladder; and iii) in those who wish to retain their 'functioning' gallbladder, to offer and select the most appropriate of the alternative options. In conclusion, despite the excellence of laparoscopic cholecystectomy, there remains a place for the non-surgical/minimally invasive approaches in a carefully selected minority of symptomatic GBS patients. Although GBS may recur in approximately 50% of patients, the recurrent stones are often asymptomatic, can be detected 'early' by follow-up ultrasound, and are easily treated. Ultimately, the aim of gallstone research must be to prevent not only recurrent but also primary GBS formation, which would obviate the need for both medical and surgical treatment.

Unexpected findings in gastrointestinal tract surgery

We discussed the proper management of patients with asymptomatic lesions incidentally found during laparotomy for other problems. For common or important lesions, information about the natural history, significance, treatment guidelines, and possible risks or complications related to operations on such incidentalomas were given. Thus, we discussed gallstones, masses of the upper and lower gastrointestinal tract, and masses in solid organs, such as liver, ovaries, and pancreas.

Laparoscopic cholecystectomy

Laparoscopic cholecystectomy is a newly developed technique for removing the gallbladder. Its future is very promising and this operation will probably become the preferred method of cholecystectomy for most patients. However, the limitations of laparoscopic cholecystectomy should be realized and great care must be taken to avoid technical complications. If laparoscopic cholecystectomy is associated with a much higher incidence of injuries to the bile duct than is traditional open cholecystectomy, its promise of decreasing pain, disability, and costs to patients undergoing cholecystectomy will be unfulfilled. The practicing general surgeon should learn laparoscopic techniques, since much of the future of abdominal surgery will ultimately reside in applying "less invasive" methods to perform standard operations. When embarking on a new procedure such as laparoscopic cholecystectomy, it is imperative that the surgeon remember the basis of his or her craft, primum non nocere.