Role of skin biopsy to confirm suspected acute graft-vs-host disease: results of decision analysis.

OBJECTIVE: To estimate the value of skin biopsy in the evaluation of suspected acute cutaneous graft-vs-host disease (GVHD) after allogeneic stem cell transplantation.

DESIGN: Decision analysis using parameters specified by expert opinion for skin biopsy characteristics, prevalence of acute GVHD, and value of potential outcomes. One-, 2-, and 3-way sensitivity analyses were performed.

SETTING: Major stem cell transplantation centers in the United States.

PATIENTS: Hypothetical cohort of patients with suspected acute cutaneous GVHD after stem cell transplantation.

INTERVENTIONS: The following 3 interventions were compared: treat immediately for GVHD without performing a skin biopsy, perform a skin biopsy and treat immediately but stop treatment if skin biopsy specimen findings are inconsistent with GVHD, and perform a skin biopsy and await results of the skin biopsy specimen before treating.

MAIN OUTCOME MEASURES: Number of patients appropriately and inappropriately treated with each intervention, consistency of physician-reported behavior, individualized decision analyses, and preferred intervention based on the aggregate estimates of respondents.

RESULTS: The decision to treat immediately for GVHD without performing a skin biopsy yielded the best clinical outcome for the specified clinical setting and under the parameters specified by expert opinion. One-way sensitivity analyses showed that these conclusions are robust if the prevalence of acute cutaneous GVHD in stem cell recipients with rash is greater than 50%, if the sensitivity of skin biopsy specimen is less than 0.8, and the specificity of skin biopsy specimen is less than 0.9. Only 25% of physicians interviewed chose an intervention consistent with their estimates of prevalence, test characteristics, and outcome evaluations, indicating an opportunity to improve management of this important clinical condition.

CONCLUSIONS: This decision analysis modeling technique predicts that in patient populations in which the prevalence of GVHD is 30% or greater (typical for allogeneic stem cell transplantation), the best outcomes were obtained with treatment for GVHD and no skin biopsy. In populations with prevalence of GVHD of 30% or less, obtaining a skin biopsy specimen to guide treatment was predicted to provide the best patient outcomes.