Why should surgeons care about clinical research methodology?

BACKGROUND: A low prevalence of high-level clinical studies in the surgical literature has been reported previously. We reviewed a recent sample of surgical publications to assess the current status of clinical research. STUDY DESIGN: A 3-month sample of journal articles in Archives of Surgery, Surgery, and Annals of Surgery in 2005 was evaluated by two independent reviewers to determine the distribution of articles in established evidence classes. RESULTS: A total of 133 publications were identified in the three journals during the time periods reviewed, including 101 clinical articles and 30 basic science articles. Among the clinical papers, there were 8 class I studies (7.9%), 34 class II studies (33.7%), and more than half were class III studies (59 of 101, or 58.4%). CONCLUSIONS: The low prevalence of high-level evidence to guide surgical management of patients persists in major general surgery journals. We believe that education about proper research methodology is not only important for researchers, but is also important for practicing surgeons, and can have important health policy implications as well.

Hypercalcemia and pancreatic endocrine neoplasia with elevated PTH-rP: report of two new cases and subject review.

Humoral hypercalcemia of malignancy is widely associated with tumor production of parathyroid hormone related protein (PTH-rP). This peptide functions in endocrine, autocrine and paracrine mechanisms in a manner similar to PTH; increasing renal uptake of calcium, decreasing retention of phosphorous, and stimulating adenylate cyclase and phospholipase C. Although PTH-rP production has been well documented in neoplasms of the exocrine pancreas, we present here two cases of endocrine pancreatic neoplasms elaborating PTH-rP. We then review the literature of previous cases and delve into the pathophysiology of this peptide.

Reported in-hospital complications following rib resections for neurogenic thoracic outlet syndrome.

While brachial plexus injury has been described as the most common complication following thoracic outlet syndrome (TOS) operation and case series have been reported, the exact incidence rate has not been described. We conducted a retrospective analysis of 5 years (1999-2003) of the Nationwide Inpatient Sample database. Neurogenic TOS patients, rib resections, brachial plexus injuries, and vascular injuries are identified by ICD-9 diagnosis codes or procedure codes. A total of 2,016 TOS operations were identified, ranging 317-468 per year, in this database. Mean age was 37.3 years, with 1,409 (70.2%) women and 1,270 (63.0%) Caucasians. These patients were treated in a total of 392 hospitals, with an average volume of 1.03 cases per hospital per year (range 0-114). Their mean hospital length of stay was 2.51 days (median 2), with a mean total hospital charge of $16,160 in inflation-adjusted year 2005 dollars (median $11,824). The majority (1,421, or 70.5%) was treated at a teaching hospital. There were 12 brachial plexus injuries (0.60%) and 35 vascular injuries (1.74%). The rate of vascular injuries was significantly lower among teaching hospitals (1.34% vs. 2.69%, P = 0.03) and in women (1.35% vs. 2.67%, P = 0.03). Vascular injury patients had significantly longer lengths of stay (7.7 vs. 2.4 days, P < 0.001) and higher total hospital charges ($53,373 vs. $15,507, P < 0.001), while no such difference was observed among brachial plexus injury patients. On hospital discharge, brachial plexus injury following rib resection for TOS occurs in <1% of cases, while vascular injuries occur in 1-2% of cases. The low complication rates suggest that the operation can be performed safely in all patients, especially at teaching hospitals, which had significantly lower rates of vascular injuries, shorter hospital lengths of stay, and lower hospital charges. The low incidence rates of these traditional clinical measures of outcome in TOS patients suggest that the appropriate measure for TOS patient outcome would be patient-reported quality of life or functional outcomes.

Trends in the in-hospital stroke rate following carotid endarterectomy in California and Maryland.

OBJECTIVE: We examined the outcome of carotid endarterectomy (CEA) in the state of Maryland during the last decade to identify any trends in the incidence of in-hospital stroke and mortality and compared these results with the outcome of the operation throughout the state of California as a control population. METHOD: We performed a retrospective analysis of 10 years (1994 to 2003) of the Maryland and 5 years (1999 to 2003) of the California hospital discharge databases. The following patients were included in the analysis: (1) International Classification of Diseases, 9th Revision, Clinical Modification (ICD-9-CM) procedure code 38.12 (endarterectomy of the vessels of the head and neck other than intracranial vessels) in the primary coding position but not in any secondary position, or (2) the diagnosis code 433.00 to 433.91 (occlusion/stenosis, precerebral artery), or (3) the diagnosis-related group (DRG) 5 (extracranial vascular procedure). Symptomatic patients were identified by history of previous stroke (ICD-9 codes 342 or 438), transient ischemic attack (435 or 781.4), or amaurosis fugax (362.34 or 368.12). In-hospital strokes were identified by ICD-9 codes 997.0, 997.00, 997.01, and 997.09. Low-, moderate-, and high-volume surgeons were defined as performing <15, 15 to 74 and >or=75 CEAs annually. Hospital volumes were similarly classified as low for those performing 100 annually. RESULTS: In the Maryland data, 23,237 CEA cases were identified with 169 in-hospital strokes over 10 years (0.73%), whereas the 51,331 California CEAs had 232 in-hospital strokes over 5 years (0.45%). The stroke rate in Maryland was 2.12% in 1994, 1.47% in 1995, and 0.29% to 0.65% from 1996 to 2003. The decrease in strokes was more pronounced among symptomatic patients, where the rate was 3.82% in 1994, 4.44% in 1995, and 0.90% to 2.29% from 1996 to 2003. A similar decrease was identified in the asymptomatic patient population but was less pronounced: 1.64% in 1994, 0.81% in 1995, and 0.15% to 0.44% from 1996 to 2003. The low recent stroke rates were confirmed by the California data (0.44% to 0.48% from 1999 to 2003). Changes in the death rate for CEA during this time frame have not been as pronounced, from 0.33% to 0.58% for Maryland and 0.78% to 0.91% for California. CONCLUSIONS: A dramatic decrease in the in-hospital stroke rates in Maryland occurred around 1995. The stroke rates in Maryland in the past 5 years are similar to those in California during the same period. An analysis of data from the two states shows that the in-hospital stroke rate now for carotid endarterectomy is approximately 0.54%.

Preoperative and intraoperative determinants of incisional bulge following retroperitoneal aortic repair.

Although the left flank retroperitoneal incision is a useful approach for many patients undergoing major aortic reconstruction for aneurysmal and occlusive disease, it has been associated with weakening of the flank muscles, resulting in bulges varying from slight asymmetry to huge hernias. The purpose of this study was to determine if the incidence of this complication correlated with identifiable preoperative or intraoperative factors. Fifty consecutive patients undergoing aortic reconstruction via the retroperitoneal approach were followed for 1 year postoperatively for evidence of disfiguring bulges. Bulges were scored as follows: normal/mild, <1-inch protrusion; moderate, protrusion 1-2 inches; severe, protrusion >2 inches and/or pain or true herniation. Preoperatively, patients were administered a questionnaire to elicit demographic and comorbidity data. Fifty-six percent of patients developed a bulge at 1 year. In 43% of these, the bulge was deemed mild and in 54% moderate. One patient developed a severe bulge. Among preoperative comorbidities, no statistically significant correlations were found on bivariate analysis. However, likelihood ratios for bulge development of 5.5 for renal disease and 3.1 for cancer were demonstrated. Conversely, peripheral vascular disease had a likelihood ratio of 0.21 for bulge formation and emphysema, 0.28. On logistic analysis, incision >15 cm and body mass index (BMI) >23 mg/kg(2) were found to correlate strongly with bulge formation (p=0.003, odds ratio=9.1, and p=0.018, odds ratio=16.9, respectively). Together, these yielded a pseudo r (2) of 0.32. BMI >23 mg/kg(2 )was found to yield the greatest explanatory power. These same two variables were found to correlate with severity of bulge: p=0.02 for incision>5 cm and p=0.006 for BMI >23. Of note, gender, age, and extension of the incision into the interspace were not significant on logistic analysis. Preoperatively, surgeons should warn obese patients and those requiring large incisions for extensive disease of their increased risk for poor healing. Intraoperatively, surgeons should aim to minimize incision length.

A preliminary clinical scale to predict the risk of in-hospital death after carotid endarterectomy.

OBJECTIVE: Carotid endarterectomy (CEA) remains the gold standard for the treatment of carotid disease, with mortality rates generally at 0.4% to 1.7%. Controversy remains with regards to its role in the treatment of the high-risk surgical population. We developed a new clinical scale incorporating weighted risk factors into a single numerical score that correlates with the risk of in-hospital death after CEA. We propose that this tool may serve to prospectively identify the high-risk patient. METHODS: We performed a retrospective analysis of 10 years (1994 to 2003) of the Maryland hospital discharge database. Included in the analysis were patients with (1) International Classification of Diseases, 9th Revision, Clinical Modification (ICD-9-CM) procedure code 38.12 (endarterectomy of the vessels of the head and neck other than intracranial vessels) in the primary coding position but not in any secondary position, or (2) Diagnosis Code 433.00 to 433.91 (occlusion/stenosis, precerebral artery), or (3) the Diagnosis-Related Group 5 (extracranial vascular procedure). ICD codes representing preoperative conditions of the patients were identified and evaluated with stepwise regression modeling techniques for association with in-hospital deaths. Different regression models were evaluated and compared by discriminative power as measured by receiver operating characteristics (ROC) and goodness-of-fit to data as measured by r(2) and the Hosmer-Lemeshow statistic. A numeric index correlating with the risk of in-hospital death was constructed by rounding the correlation coefficients for the statistically significant variables from the logistic regression. RESULTS: We identified 23,237 cases. The mean age of patients was 70.6 years, with 54.7% male patients. There were 125 in-hospital deaths (0.54%). Patient age and four patient medical conditions emerged with significant associations with in-hospital deaths after CEA, and their relationships can be summarized in a single diagnostic scale: 1 point for age > or =75, 2 points for atherosclerosis (ICD code 440), 3 points for cardiomyopathy (ICD code 425), 4 points for iron-deficiency anemia (ICD code 280), and 5 points for cerebral degeneration (ICD code 331). This scale has moderate discriminative power (ROC = 0.67). On average, each point increase on this scale is associated with a 1.58-times increase in mortality risk, with score of 6 on the scale carrying a mortality risk >5%. CONCLUSIONS: This new 5-item scale, based on patient age and past medical history, correlates moderately with the rate of in-hospital death after CEA. This clinical index may serve to identify high-risk patients. Future improvements to this diagnostic scale should focus on the diagnostic values of additional laboratory and demographic data.

The distribution of carotid endarterectomy procedures among surgeons and hospitals in New York state: is regionalization of specialized vascular care occurring?

INTRODUCTION: In a published analysis of all carotid endarterectomies (CEAs) performed in New York state from 1990 to 1995, perioperative mortality rate was inversely correlated with surgeon and hospital CEA volume, was significantly higher when CEAs were performed by surgeons who performed less than five CEAs annually, and was significantly lower in hospitals where surgeons performed more than 100 CEAs annually. The purpose of this study was to determine whether this information has influenced practice patterns in New York state. METHODS: The database of the Center for Medical Consumers was queried to determine the volume distribution among surgeons and hospitals of all CEAs performed in New York state in 1999 and 2000. RESULTS: During 1999, 695 surgeons in 169 hospitals performed 9458 CEAs (mean, 13.6 per surgeon). Three hundred fifty-three surgeons (51%) performed less than five CEAs, and 180 (26%) performed only one CEA during the year. Only 41 surgeons (6%) performed more than 50 CEAs. Likewise, in only 28 of the hospitals (17%) were more than 100 CEAs performed during 1999, whereas in 73 of the hospitals (43%) 20 or less CEAs were carried out during the year. During 2000, 684 surgeons performed 8196 CEAs in 165 hospitals. Three hundred fifty-three (52%) performed less than five CEAs, and 229 (33%) performed only one CEA during the year. Only 33 surgeons (5%) performed more than 50 CEAs during 2000. In only 26 hospitals (16%) were more than 100 CEAs performed during 2000, whereas in 71 hospitals (43%) 20 or less CEAs were carried out. CONCLUSION: It appears that published compelling evidence that operator and institutional volume influence outcome has not influenced referral patterns or led to a regionalization of CEA care in New York state. Robust educational programs directed to patients and referring physicians appear indicated.