Learning Curve of a Laparoscopic Pancreaticoduodenectomy Program at a Second Institution

BACKGROUND

Historically, pancreaticoduodenectomy (PD) has been performed via a laparotomy, but increasingly, laparoscopic and robotic platforms are being employed for PD. Laparoscopic PD has a steep surgeon specific learning curve and programmatic elements that must be optimized. These factors may limit a surgeon who is proficient at laparoscopic PD to develop a program at another institution. We hypothesize that the learning curve for a surgeon transferring a program to a second institution is shorter than the initial laparoscopic PD learning curve for the same surgeon.

METHODS

A retrospective review of patients who underwent laparoscopic PD for any indication at the first institution (FI) from 2012 to 2017 and the second institution (SI) from 2018 to 2021 was conducted. Standard statistical analysis was performed. The learning curve was identified using one-sided CUSUM analysis of operative times.

RESULT

We identified 110 participants, 90 from the FI and 20 from the SI. More patients at the FI were diagnosed with periampullary adenocarcinoma on final pathology compared to the SI (65.6% vs 40.0%, P = .0132). FI operative times stabilized after the 25th laparoscopic PD and SI operative times stabilized after the 5th operation. No statistically significant difference was identified in postoperative complications.

CONCLUSIONS

The learning curve and average operative time of an SI laparoscopic PD program was shorter than the initial learning curve for a single surgeon with comparable outcomes. This suggests that complex minimally invasive surgical programs can be safely transferred to another high-volume institution without significant loss of progress.

Autogenic splenic implantation versus splenectomy in patients undergoing distal pancreatectomy for benign or low-grade malignant lesions of the distal pancreas: study protocol for a multicentre, open-label, randomized controlled trial (RESTORE)

BACKGROUND

The spleen plays a significant role in the clearance of circulating microorganisms. Sequelae of splenectomy, especially immunodeficiency, can have a deleterious effect on a patient's health and even lead to death. Hence, splenectomy should be avoided and spleen preservation during elective surgery has become a treatment goal. However, this cannot be achieved in every patient due to intraoperative technical difficulties or oncological reasons. Autogenic splenic implantation (ASI) is currently the only possible way to preserve splenic function when a splenectomy is necessary. Experience largely stems from trauma patients with a splenic rupture. Splenic immune function can be measured by the body's clearing capacity of encapsulated bacteria. The aim of this study is to assess the splenic immune function after ASI was performed during minimally invasive (laparoscopic or robotic) distal pancreatectomy with splenectomy.

METHODS

This is the protocol for a multicentre, randomized, open-labelled trial. Thirty participants with benign or low-grade malignant lesions of the distal pancreas requiring minimally invasive distal pancreatectomy and splenectomy will be allocated to either additional intraoperative ASI (intervention) or no further intervention (control). An additional 15 patients who will undergo spleen-preserving distal pancreatectomy serve as the control group with normal splenic function. Six months postoperatively, after assumed restoration of splenic function, patients will be given a Salmonella typhi (Typhim Vi™) vaccine. The Salmonella typhi vaccine is a polysaccharide vaccine. The specific antibody titres immediately before and 4 to 6 weeks after vaccination will be measured. The ratio between pre- and post-vaccination antibody count is the primary outcome measure and secondary outcome measures include intraoperative details, length of hospital stay, 30-day mortality and morbidity.

DISCUSSION

This study will investigate the splenic immune function of patients who undergo ASI during minimally invasive distal pancreatectomy with splenectomy. The splenic immune function will be measured using the surrogate outcome of specific antibody titre after vaccination with a Salmonella typhi vaccine. The results will reveal details about splenic function after ASI and guide further treatment options for patients when a splenectomy cannot be avoided. It might eventually lead to a new standard of care making sometimes more demanding and time-consuming spleen-preserving procedures redundant.

TRIAL REGISTRATION

International Standard Randomized Controlled Trials Number (ISRCTN) ISRCTN10171587. Prospectively registered on 18 February 2019.

Not all cholecystitis is created equal: Disparities contributing to ED presentation and failure of the outpatient algorithm

BACKGROUND

The majority of final surgical pathology (FSP) from both emergency department (ED) and outpatient clinic (OC) patients is chronic cholecystitis. We aimed to differentiate these presentations and identify disparities associated with ED utilization and OC failure.

METHODS

Retrospective chart review of single institution ED and OC cholecystectomies for cholelithiasis. Clinical presentation, FSP, demographics, and zip code poverty (ZCP) levels were evaluated. Data analysis by summary statistics, bivariate comparisons, and logistic regression.

RESULTS

Of 299 OC and 308 ED patients, OC was more likely to be Caucasian (78% vs 46%, p < 0.0001) and insured (89% vs. 32%, p < 0.0001). 71.8% of OC with ZCP <10% had insurance versus only 32.5% in ZCP >20%. Uninsured ED OR was 13.1 (95% CI 8.7-22.9).

CONCLUSION

Uninsured ED patients are vulnerable to fail the outpatient algorithm, especially when misdiagnosed by US. Clinical diagnosis of cholecystitis in this population should warrant offering of urgent cholecystectomy.

Innovative Imaging Techniques Used to Evaluate Borderline-Resectable Pancreatic Adenocarcinoma

A diagnosis of pancreatic cancer carries a 5-y survival rate of less than 10%. Furthermore, the detection of pancreatic cancer occurs most often in later stages of the disease due to its location in the retroperitoneum and lack of symptoms (in most cases) until tumors become more advanced. Once diagnosed, cross-sectional imaging techniques are heavily utilized to determine the tumor stage and the potential for surgical resection. However, a major determinant of resectability is the extent of local vascular involvement of the mesenteric vessels and critical tributaries; current imaging techniques have limited capacity to accurately determine vascular involvement. Surrounding inflammation and fibrosis can be difficult to discriminate from viable tumor, making determination of the degree of vascular involvement unreliable. New innovations in fluorescence and optoacoustic imaging techniques may overcome these limitations and make determination of resectability more accurate. These imaging modalities are able to more clearly discern between viable tumor tissue and non-neoplastic inflammation or desmoplasia, allowing clinicians to more reliably characterize vascular involvement and develop individualized treatment plans for patients. This review will discuss the current imaging techniques used to diagnose pancreatic cancer, the barriers that current techniques raise to accurate staging, and novel fluorescence and optoacoustic imaging techniques that may provide more accurate clinical staging of pancreatic cancer.

Surgical and Oncological Outcomes After Preoperative FOLFIRINOX Chemotherapy in Resected Pancreatic Cancer: An International Multicenter Cohort Study

BACKGROUND

Preoperative FOLFIRINOX chemotherapy is increasingly administered to patients with borderline resectable (BRPC) and locally advanced pancreatic cancer (LAPC) to improve overall survival (OS). Multicenter studies reporting on the impact from the number of preoperative cycles and the use of adjuvant chemotherapy in relation to outcomes in this setting are lacking. This study aimed to assess the outcome of pancreatectomy after preoperative FOLFIRINOX, including predictors of OS.

METHODS

This international multicenter retrospective cohort study included patients from 31 centers in 19 European countries and the United States undergoing pancreatectomy after preoperative FOLFIRINOX chemotherapy (2012-2016). The primary end point was OS from diagnosis. Survival was assessed using Kaplan-Meier analysis and Cox regression.

RESULTS

The study included 423 patients who underwent pancreatectomy after a median of six (IQR 5-8) preoperative cycles of FOLFIRINOX. Postoperative major morbidity occurred for 88 (20.8%) patients and 90-day mortality for 12 (2.8%) patients. An R0 resection was achieved for 243 (57.4%) patients, and 259 (61.2%) patients received adjuvant chemotherapy. The median OS was 38 months (95% confidence interval [CI] 34-42 months) for BRPC and 33 months (95% CI 27-45 months) for LAPC. Overall survival was significantly associated with R0 resection (hazard ratio [HR] 1.63; 95% CI 1.20-2.20) and tumor differentiation (HR 1.43; 95% CI 1.08-1.91). Neither the number of preoperative chemotherapy cycles nor the use adjuvant chemotherapy was associated with OS.

CONCLUSIONS

This international multicenter study found that pancreatectomy after FOLFIRINOX chemotherapy is associated with favorable outcomes for patients with BRPC and those with LAPC. Future studies should confirm that the number of neoadjuvant cycles and the use adjuvant chemotherapy have no relation to OS after resection.

Risk Factors Associated With Readmission After Pancreatectomy: A Single-Institution Retrospective Cohort Study

BACKGROUND

Pancreatectomy has a significant rate of procedure-specific morbidity which can result in readmission. Readmission has been proposed as a measure of quality. The goal of this study is to determine what factors are associated with readmission after pancreatectomy and whether readmission can be prevented.

METHODS

A retrospective review of a single institution's pancreatectomies between January 2011 and April 2015 was performed. Demographic, perioperative, and outpatient data were collected from the medical record. Primary outcome was 90-day readmission. Univariate and multivariable analyses were performed to determine which factors were associated with increased risk for readmission.

RESULTS

A total of 257 patients met inclusion criteria; the 90-day readmission rate was 32.7%. The median time to readmission was 13 days. Readmitted patients were more likely to have a postoperative pancreatic fistula (POPF) on univariate analysis. Surgical site infections were more common in readmitted patients (18% vs 6.4%, P = .0138). Upon multivariable adjustment, only POPF (P = .0005) remained significant. A positive dose-response relationship was noted between POPF grade and the odds of readmission with odds ratios (ORs) ranging from 1.6 (95% Confidence Interval (CI): .6-4.1) for grade A to 16.7 (95% CI: 1.8-156.8) for grade C, albeit with limited precision.

CONCLUSIONS

Readmission after pancreatectomy is a common occurrence despite the many advancements in perioperative care. Our data suggest that POPF is a risk factor for readmission after pancreatectomy. Presently, this factor is not clearly preventable. This suggests that readmission may not be the best measure of quality to utilize in the evaluation of pancreatic surgery.

Evaluation of Adjuvant Chemotherapy in Patients With Resected Pancreatic Cancer After Neoadjuvant FOLFIRINOX Treatment

Importance

The benefit of adjuvant chemotherapy after resection of pancreatic cancer following neoadjuvant combination treatment with folinic acid, fluorouracil, irinotecan, and oxaliplatin (FOLFIRINOX) is unclear.

Objective

To assess the association of adjuvant chemotherapy with overall survival (OS) in patients after pancreatic cancer resection and neoadjuvant FOLFIRINOX treatment.

Design, Setting, and Participants

This international, multicenter, retrospective cohort study was conducted from January 1, 2012, to December 31, 2018. An existing cohort of patients undergoing resection of pancreatic cancer after FOLFIRINOX was updated and expanded for the purpose of this study. All consecutive patients who underwent pancreatic surgery after at least 2 cycles of neoadjuvant FOLFIRINOX chemotherapy for nonmetastatic pancreatic cancer were retrospectively identified from institutional databases. Patients with resectable pancreatic cancer, borderline resectable pancreatic cancer, and locally advanced pancreatic cancer were eligible for this study. Patients with in-hospital mortality or who died within 3 months after surgery were excluded.

Exposures

The association of adjuvant chemotherapy with OS was evaluated in different subgroups including interaction terms for clinicopathological parameters with adjuvant treatment in a multivariable Cox model. Overall survival was defined as the time starting from surgery plus 3 months (moment eligible for adjuvant therapy), unless mentioned otherwise.

Results

We included 520 patients (median [interquartile range] age, 61 [53-66] years; 279 [53.7%] men) from 31 centers in 19 countries. The median number of neoadjuvant cycles of FOLFIRINOX was 6 (interquartile range, 5-8). Overall, 343 patients (66.0%) received adjuvant chemotherapy, of whom 68 (19.8%) received FOLFIRINOX, 201 (58.6%) received gemcitabine-based chemotherapy, 14 (4.1%) received capecitabine, 45 (13.1%) received a combination or other agents, and 15 (4.4%) received an unknown type of adjuvant chemotherapy. Median OS was 38 months (95% CI, 36-46 months) after diagnosis and 31 months (95% CI, 29-37 months) after surgery. No survival difference was found for patients who received adjuvant chemotherapy vs those who did not (median OS, 29 vs 29 months, univariable hazard ratio [HR], 0.99; 95% CI, 0.77-1.28; P = .93). In multivariable analysis, only the interaction term for lymph node stage with adjuvant therapy was statistically significant: In patients with pathology-proven node-positive disease, adjuvant chemotherapy was associated with improved survival (median OS, 26 vs 13 months; multivariable HR, 0.41 [95% CI, 0.22-0.75]; P = .004). In patients with node-negative disease, adjuvant chemotherapy was not associated with improved survival (median OS, 38 vs 54 months; multivariable HR, 0.85; 95% CI, 0.35-2.10; P = .73).

Conclusions and Relevance

These results suggest that adjuvant chemotherapy after neoadjuvant FOLFIRINOX and resection of pancreatic cancer was associated with improved survival only in patients with pathology-proven node-positive disease. Future randomized studies should be conducted to confirm this finding.

Practicing on the Advanced Training in Laparoscopic Suturing Curriculum (ATLAS): Is Mastery Learning in Residency Feasible to Achieve Expert-Level Performance in Laparoscopic Suturing?

BACKGROUND

Mastery learning assumes that given enough time and appropriate instructional strategies, most trainees will be able to achieve proficiency. Expert-level performance requires numerous hours of intensive and focus practice. We aimed to study whether it was possible for surgical trainees to achieve expert-derived proficiency level in laparoscopic suturing using the Advanced Training in Laparoscopic Suturing (ATLAS) curriculum over a short period of time.

STUDY DESIGN

A multicenter IRB approved prospective study included surgery residents and minimally invasive fellows. Participants underwent weekly supervised instruction and assessments of ATLAS skills and self-directed practice between sessions over 12 weeks. Participants were asked to practice until they achieved previously established proficiency benchmarks of expert laparoscopic surgeons.

RESULTS

Fifteen participants, PGY2 to PGY6, from 3 institutions practiced on the ATLAS curriculum. Three participants were able to achieve proficiency on the entire curriculum, with a cumulative practice time varying between 3.4 and 7.6 hours. Individual tasks had varying degrees of difficulty ranging from 85% proficiency on task 1 to 33.3% proficiency for task 6. Using a mixed-method model, the mean cumulative hours of practice to reach the benchmark threshold was estimated for each task and varied from 4.5 to 13.2 hours. The improved performance was associated with higher PGY level and proficiency in FLS.

CONCLUSIONS

This study demonstrates that it is possible for some senior surgical trainees to achieve proficiency in an expert-level laparoscopic suturing curriculum. This study establishes a learning curve for each ATLAS individual task. Some learners may not be able to achieve proficiency on the entire curriculum over a short period of practice. Additional studies are needed to assess how to shorten the learning curve with effective instructional methods such as expert-guided training with immediate feedback.

Gemcitabine-based adjuvant chemotherapy in subtypes of ampullary adenocarcinoma: international propensity score-matched cohort study

BACKGROUND

Whether patients who undergo resection of ampullary adenocarcinoma have a survival benefit from adjuvant chemotherapy is currently unknown. The aim of this study was to compare survival between patients with and without adjuvant chemotherapy after resection of ampullary adenocarcinoma in a propensity score-matched analysis.

METHODS

An international multicentre cohort study was conducted, including patients who underwent pancreatoduodenectomy for ampullary adenocarcinoma between 2006 and 2017, in 13 centres in six countries. Propensity scores were used to match patients who received adjuvant chemotherapy with those who did not, in the entire cohort and in two subgroups (pancreatobiliary/mixed and intestinal subtypes). Survival was assessed using the Kaplan-Meier method and Cox regression analyses.

RESULTS

Overall, 1163 patients underwent pancreatoduodenectomy for ampullary adenocarcinoma. After excluding 187 patients, median survival in the remaining 976 patients was 67 (95 per cent c.i. 56 to 78) months. A total of 520 patients (53·3 per cent) received adjuvant chemotherapy. In a propensity score-matched cohort (194 patients in each group), survival was better among patients who received adjuvant chemotherapy than in those who did not (median survival not reached versus 60 months respectively; P = 0·051). A survival benefit was seen in patients with the pancreatobiliary/mixed subtype; median survival was not reached in patients receiving adjuvant chemotherapy and 32 months in the group without chemotherapy (P = 0·020). Patients with the intestinal subtype did not show any survival benefit from adjuvant chemotherapy.

CONCLUSION

Patients with resected ampullary adenocarcinoma may benefit from gemcitabine-based adjuvant chemotherapy, but this effect may be reserved for those with the pancreatobiliary and/or mixed subtype.

Neuroendocrine Tumors of the Pancreatobiliary and Gastrointestinal Tracts

Incidence of neuroendocrine tumors (NETs) is increasing, including those of the gastroenteropancreatic tract. A proper understanding of the management of this disease has become necessary for the general surgeon. This article addresses current guidelines for diagnosis and localization of NETs, including somatostatin receptor PET. Updated treatment and outcomes of NETs by primary tumor site are discussed as well as those metastatic to the liver.

Contemporary Review of Borderline Resectable Pancreatic Ductal Adenocarcinoma

Borderline resectable pancreatic adenocarcinoma (PDAC) presents challenges in definition and treatment. Many different definitions exist for this disease. Some are based on anatomy alone, while others include factors such as disease biology and patient performance status. Regardless of definition, evidence suggests that borderline resectable PDAC is a systemic disease at the time of diagnosis. There is high-level evidence to support the use of neoadjuvant systemic therapy in these cases. Evidence to support the use of radiation therapy is ongoing. There are ongoing trials investigating the available neoadjuvant therapies for borderline resectable PDAC that may provide clarity in the future.

Association of unconscious race and social class bias with vignette-based clinical assessments by medical students

CONTEXT

Studies involving physicians suggest that unconscious bias may be related to clinical decision making and may predict poor patient-physician interaction. The presence of unconscious race and social class bias and its association with clinical assessments or decision making among medical students is unknown.

OBJECTIVE

To estimate unconscious race and social class bias among first-year medical students and investigate its relationship with assessments made during clinical vignettes.

DESIGN, SETTING, AND PARTICIPANTS

A secure Web-based survey was administered to 211 medical students entering classes at Johns Hopkins School of Medicine, Baltimore, Maryland, in August 2009 and August 2010. The survey included the Implicit Association Test (IAT) to assess unconscious preferences, direct questions regarding students' explicit race and social class preferences, and 8 clinical assessment vignettes focused on pain assessment, informed consent, patient reliability, and patient trust. Adjusting for student demographics, multiple logistic regression was used to determine whether responses to the vignettes were associated with unconscious race or social class preferences.

MAIN OUTCOME MEASURES

Association of scores on an established IAT for race and a novel IAT for social class with vignette responses.

RESULTS

Among the 202 students who completed the survey, IAT responses were consistent with an implicit preference toward white persons among 140 students (69%, 95% CI, 61%-75%). Responses were consistent with a preference toward those in the upper class among 174 students (86%, 95% CI, 80%-90%). Assessments generally did not vary by patient race or occupation, and multivariable analyses for all vignettes found no significant relationship between implicit biases and clinical assessments. Regression coefficient for the association between pain assessment and race IAT scores was -0.49 (95% CI, -1.00 to 0.03) and for social class, the coefficient was -0.04 (95% CI, -0.50 to 0.41). Adjusted odds ratios for other vignettes ranged from 0.69 to 3.03 per unit change in IAT score, but none were statistically significant. Analysis stratified by vignette patient race or class status yielded similarly negative results. Tests for interactions between patient race or class status and student IAT D scores in predicting clinical assessments were not statistically significant.

CONCLUSIONS

The majority of first-year medical students at a single school had IAT scores consistent with implicit preference for white persons and possibly for those in the upper class. However, overall vignette-based clinical assessments were not associated with patient race or occupation, and no association existed between implicit preferences and the assessments.

Effect of isoniazid chemoprophylaxis on HIV-related mycobacterial disease

OBJECTIVES

The aims of this study were to (1) identify trends and risk factors for mycobacterial disease and (2) determine the effect of expanded access to isoniazid chemoprophylaxis on tuberculosis incidence.

METHODS

A prospective observational cohort study was conducted among community-based injecting drug users (IDUs); 2960 IDUs (942 human immunodeficiency virus [HIV] seropositive) were followed up from January 1988 to June 1994. Directly observed chemoprophylaxis with twice-weekly isoniazid (10 to 15 mg/kg) was offered to purified protein derivative (PPD) tuberculin-positive (> or = 5-mm induration diameter in HIV-seropositive subjects and > or = 10-mm diameter in HIV-seronegative subjects) individuals but not to those with cutaneous anergy. Overall and annual incidence rates of disease due Mycobacterium tuberculosis, Mycobacterium avium complex, and other atypical mycobacteria were estimated using Poisson regression.

RESULTS

HIV seropositivity was the strongest risk factor for tuberculosis, M avium complex, and other mycobacterial disease (relative risk [RR], 3.8, 17.2, and 6.9, respectively). Median CD4 lymphocyte cell counts for the three groups of mycobacterial disease were 0.17, 0.03, and 0.02 x 10(9)/L (167/microL, 30/microL, 18/microL) within 6 months of diagnosis (before or after). Overall incidence rates of tuberculosis, M avium complex disease, and other mycobacterial disease were 1.9, 8.8, and 2.7 per 1000 person-years, respectively. Tuberculosis incidence peaked in 1991 at six per 1000 person-years. However, after access to directly observed preventive therapy was expanded for tuberculin-positive subjects, incidence fell to only one case in 1992 and zero cases for 24 months from mid-1992 to mid-1994. During this period the number of PPD-positive patients who completed at least 26 weeks of therapy (or were still receiving isoniazid) more than tripled (from 21 to 70). None of the 12 patients with tuberculosis diagnosed during follow-up had received any preventive therapy. In addition, no tuberculosis developed among participants with cutaneous anergy. Calendar trends in risk for M avium complex and tuberculosis diverged after expanded access to isoniazid prophylaxis. Compared with 1988-1989, risk of M avium complex increased sevenfold. Tuberculosis risk fell 83% from the peak risk in 1990-1991.

CONCLUSIONS

Expanded access to directly observed isonazid therapy for tuberculin-positive IDUs with and without HIV infection was associated with an 83% drop in tuberculosis incidence, while in the same period M avium complex incidence significantly increased. These population-based data are consistent with those obtained from clinical trials of isoniazid prophylaxis and were obtained without offering chemoprophylaxis to HIV-infected patients with cutaneous energy.

Prevalence of tuberculin positivity and skin test anergy in HIV-1-seropositive and -seronegative intravenous drug users

OBJECTIVES

--To identify differences in purified protein derivative (PPD) tuberculin positivity and skin test anergy rates by human immunodeficiency virus (HIV) serostatus, CD4+ lymphocyte count, and other risk factors in intravenous drug users (IVDUs); and to evaluate the appropriateness of the Centers for Disease Control (CDC)--recommended definition for a positive PPD tuberculin skin test result in HIV-1-seropositive patients.

DESIGN

--Nested case-control and cross-sectional analyses.

SETTING

--Community-based cohort of IVDUs.

PATIENTS

--Two hundred sixty HIV-1-seropositive and -seronegative IVDUs, drawn from an unselected cohort, were skin-tested for sensitivity to PPD tuberculin, mumps, and Candida antigens using the Mantoux method.

OUTCOME MEASURES

--Positivity to PPD tuberculin, skin test anergy.

RESULTS

--Even using the CDC definition of an induration 5 mm or greater in diameter in HIV-1 seropositives, this group was substantially less likely to be PPD tuberculin positive than HIV-1 seronegatives (13.8% vs 25.2%; P = .02). In the HIV-1 seropositives the relative odds of being PPD positive varied depending on whether 10 mm or greater (odds ratio [OR], 0.3; 95% confidence interval [CI], 0.2 to 0.7), 5 mm or greater (OR, 0.5; 95% CI, 0.2 to 0.9), or 2 mm or greater (OR, 0.7; 95% CI, 0.4 to 1.3) was used to define a positive test result. The mean diameter induration in the HIV-1-seropositive group was 2.6 mm vs 5.4 mm in the seronegative group (P = .005). Skin test anergy (to mumps and Candida) appeared to explain the differential. Anergy was substantially higher in the HIV-1 seropositive group and increased as the CD4+ lymphocyte count fell (chi 2 for linear trend, 24.5; P less than .0001). An inverse linear trend for PPD positivity and CD4+ lymphocyte count was also observed (chi 2 for trend, 6.1; P = .01). In multivariate analyses, being 35 years of age or older and being HIV-1 seronegative were significantly associated with PPD positivity, while history of previous police arrest was of borderline significance. Only HIV-1 seropositivity was significantly associated with anergy.

CONCLUSIONS

--These findings show that CDC-recommended definition of an induration 5 mm or greater in diameter for PPD tuberculin positivity in HIV-1 seropositives significantly underestimates the "true" infection rate (using the PPD positivity rate in HIV-1 seronegatives as the criterion standard). A definition of 2 mm or greater would appear to be a better cutoff for reducing misclassification in HIV-1 seropositives. This study also confirms that delayed-type hypersensitivity is seriously depressed in HIV-1 seropositive IVDUs and that anergy testing is mandatory to properly assess a negative PPD test result.