Pediatrics/original research
Evaluating Appendicitis Scoring Systems Using a Prospective Pediatric Cohort

Presented at the Pediatric Academic Societies meeting, May 2006, San Francisco, CA.
https://doi.org/10.1016/j.annemergmed.2006.12.016Get rights and content

Study objective

This article evaluates the performance of the previously published Alvarado and Samuel appendicitis scoring systems in a prospectively identified pediatric cohort.

Methods

A prospective cohort of patients, aged 3 to 21 years, being evaluated for appendicitis was enrolled during 20 consecutive months at a large, urban, pediatric hospital. Study forms were completed by pediatric emergency medicine attending physicians before imaging or surgery. Final diagnosis was determined by pathology or follow-up telephone call. Each score was tested as proposed by the original authors. Sensitivity, specificity, and predictive values were calculated for all patients and prepubertal patients younger than 10 years.

Results

Five hundred eighty-eight patients were studied. The median age was 11.9 years (interquartile range [IQR] 8.5; 14.9 years). Thirty-four percent of patients had appendicitis. An Alvarado score greater than or equal to 7 yielded a sensitivity of 72% (95% confidence interval [CI] 66% to 78%), specificity 81% (76% to 84%), negative predictive value (NPV) 85% (81% to 89%), and positive predictive value (PPV) 65% (59% to 72%). A Samuel score greater than or equal to 6 yielded a sensitivity of 82% (77% to 87%), specificity 65% (60% to 70%), NPV 88% (84% to 91%), and PPV 54% (48% to 60%). When analysis was limited to patients younger than 10 years, n=206, an Alvarado score greater than or equal to 7 yielded a sensitivity of 73% (62% to 84%), specificity 80% (73% to 86%), NPV 89% (83% to 94%), and PPV 58% (45% to 69%). A Samuel score greater than or equal to 6, when patients younger than 10 years were considered, yielded a sensitivity of 77% (66% to 87%), specificity 65% (56% to 72%), NPV 88% (82% to 94%), and PPV 45% (35% to 55%). Receiver operator characteristic curves had an area under the curve of 0.83 (95% CI 0.79 to 0.86) (Alvarado) and 0.81 (95% CI 0.78 to 0.85) (Samuel).

Conclusion

Although the Alvarado and Samuel scores provide measurably useful diagnostic information in evaluating children with suspected appendicitis, neither method provides sufficient PPV to be used in clinical practice as the sole method for determination of the need for surgery.

Introduction

Appendicitis is one of the most common causes of acute abdominal pain in pediatrics and is the most common indication for emergency abdominal surgery in childhood.1 Despite substantial research, the diagnosis of pediatric appendicitis remains challenging. Recent studies have proposed different methods to treat children presenting to the emergency department (ED) with symptoms suggestive of appendicitis.2, 3, 4, 5 Clinical scores used in these studies have relied on historical, physical examination, and laboratory findings. Ideally, a clinical score could accurately distinguish those patients that need immediate operative care from those that may benefit from further investigation or observation. Two pediatric appendicitis scoring systems, published by Alvarado6 and Samuel,7 are the most widely referenced in the literature.3 Neither score has been validated.

A clinical scoring system should be validated in a different sample before widespread use. The original intent of both Alvarado6 and Samuel7 was to determine which patients required operative care. A pediatric appendicitis score that aided clinical diagnosis would be valuable to the emergency medicine clinician.

The objective of this study is to evaluate the performance of Alvarado’s6 and Samuel’s7 scoring systems in a prospectively identified cohort of pediatric patients with suspected appendicitis. As intended by the original authors, the test-performance characteristics of each score for determining operative care will be presented.

Section snippets

Study Design and Setting

This prospective observational study was conducted from July 2003 to December 2004 at a tertiary pediatric medical center, with an ED volume of 52,000 visits per year. A portion of this data set was previously published as a clinical decision rule identifying low risk for appendicitis.2

Selection of Participants

Children between 3 and 21 years of age, with suspected appendicitis, were enrolled; entry into the study required surgical consultation for possible appendicitis. Any patient who is treated by a pediatric

Results

During the period of enrollment, 6,120 patients were treated in the ED for abdominal pain. Of the patients with abdominal pain, 821 had a surgical consultation for possible appendicitis. We captured 92% of eligible patients, or 755 patients, who had suspected appendicitis. Of the 755 patients enrolled, 588 patients (78%) had complete data to compute a Samuel and Alvarado score. All 588 patients had operative care (37%) or follow-up (63%). The 167 patients with missing data were missing the

Limitations

Our study sample consisted of children undergoing evaluation for possible appendicitis, as determined by a pediatric emergency physician; this sample likely will vary from that of other pediatric centers. In addition, our study sample had a relatively high prevalence of appendicitis, and therefore the scoring systems’ performance should not be generalized to a population of nonspecific abdominal pain. Additionally, the symptomatology and signs of appendicitis are a function of timing of

Discussion

The original article by Alvarado6 retrospectively investigated 305 patients who were admitted to the hospital with abdominal pain suggestive of appendicitis. Although not explicitly written in the published article, the test performance of the score can be calculated according to available data: sensitivity 81%, specificity 74%, PPV 92%, and NPV 46%.

Additional validation of the Alvarado score has had mixed results. Hsiao et al8 performed a case-control retrospective study, applying the Alvarado

References (21)

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    Citation Excerpt :

    A requirement for institutional review board (IRB) approval was waived based on the QI nature of the initiative. The pathway utilized the Alvarado Score (AS), one of several validated pediatric appendicitis scoring tools which combines historical symptoms, clinical signs, and laboratory findings, to stratify patients into low, moderate, and high risk groups for any child who was considered to have possible appendicitis based on initial EM physician assessment [1–14]. The choice of the AS tool was made by the EM physicians, with cut-offs for the low- and high- risk categories based on a published optimization study [4].

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Supervising editor: David M. Jaffe, MD

Author contributions: AK and RB conceived the study and designed the trial. AK and RB supervised the conduct of the trial and data collection. AK and RB undertook recruitment of patients and managed the data, including quality control. RB provided statistical advice on study design, RB takes responsibility for all statistical calculations in the manuscript, CS and RB analyzed the data, CD drafted the manuscript, and all authors contributed substantially to its revision. CD, AK and RB take responsibility for the paper as a whole.

Funding and support: The authors report this study did not receive any outside funding or support.

Publication dates: Available online March 26, 2007.

Reprints not available from the authors.

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