IS THE INCIDENCE OF APPENDICITIS REDUCED IN PATIENTS WITH SICKLE-CELLDISEASE

Background. Patients with sickle cell disease (SCD) often present with abdominal pain, usually attributable to vasoocclusion. Experience at a single institution suggested that appendicitis was a rare cause of a bdominal symptoms in this population. Objective. We sought to determin e whether the incidence of appendicitis was significantly lower in pat ients with SCD than in the population at large. Methods. A 17-year ret rospective chart review was performed at Rainbow Babies and Children's Hospital, Cleveland, OH, to determine the approximate incidence of ac ute appendicitis (AA) in patients with SCD. In addition, we performed a statistical analysis comparing the incidence of AA among SCD patient s enrolled in the Cooperative Study of Sickle Cell Disease with that i n the general population. Results. Only two patients with SCD with pat hologically confirmed AA were identified among similar to 200 patients followed at our institution during a 17-year period (similar to 3500 patient-years), yielding an incidence rate of 5.7 cases per 10 000 pat ient-years. Among 3765 patients with SCD enrolled in the Cooperative S tudy of Sickle Cell Disease followed for a mean of 5.3 years (19 886 p atient-years), a maximum of 9 cases of AA were identified, yielding an incidence rate of 4.5 cases per 10 000 patient-years. Based on data f rom the National Hospital Discharge Survey of 1978 to 1981, the incide nce rate of AA in the general population (0 to 44 years of age) is sim ilar to 16 per 10 000 patient-years. Paired t test analysis demonstrat ed a highly significant difference (P < .001) when comparing the incid ence of AA among patients enrolled in the Cooperative Study of Sickle Cell Disease and the population at large. Conclusion. AA is an unusual event in patients with SCD. The likelihood of developing appendicitis in SCD patients is less than one third of that for the population at large. Conservative therapy is warranted in the large majority of pati ents with SCD who present with acute abdominal pain. Surgical explorat ion is best limited to patients with clear evidence of potential surgi cal pathology or progressive findings during a period of observation. The biologic basis of our findings remains unknown.