In reply:

Abstract

Before we address the specifics raised by Moore et al, we would like to emphasize that renal colic is largely a clinical diagnosis, and in the right patient with the right history, physical examination result, and urinalysis result, advanced imaging can be deferred and watchful waiting with pain control is the preferred treatment strategy. As stressed in our editorial,1Green S.M. Schriger D.L. The sinking STONE: what a failed validation can teach us about clinical decision rules.Ann Emerg Med. 2016; 67: 433-436Abstract Full Text Full Text PDF PubMed Scopus (8) Google Scholar a clinical decision rule is effectively invalidated when one of its core components cannot be independently replicated as predictive,2Green S.M. Schriger D.L. Yealy D.M. Methodologic standards for interpreting clinical decision rules in emergency medicine: 2014 update.Ann Emerg Med. 2014; 64: 286-291Abstract Full Text Full Text PDF PubMed Scopus (55) Google Scholar particularly when the replication study is substantially larger than the source validation study, as has occurred with Wang et al.3Wang R.C. Rodriguez R.M. Moghadassi M. et al.External validation of the STONE score, a clinical prediction rule for ureteral stone: an observational multi-institutional study.Ann Emerg Med. 2016; 67: 423-432Abstract Full Text Full Text PDF PubMed Scopus (42) Google Scholar The counterargument that, despite nonreplication, nonblack race has a soft statistical association with kidney stones hardly makes such a variable reliable enough—and thus suitable for—inclusion in a decision rule. As a result, we believe that the STONE score has failed and should not be used clinically unless and until it can be refined, or ideally reformulated to guide specific clinical decisionmaking (eg, when to image) rather than its limited current role of general risk sorting. The two “positive” study validations referred to by Moore et al do not advance the discourse because they mirror the key methodological limitations of the original study: promoting general risk sorting over specific decisionmaking, and identifying the presence or absence of stones rather than clinically important outcomes, ie, serious alternative diagnoses or indications for urgent urologic intervention. These problems were discussed in detail in our original editorial,1Green S.M. Schriger D.L. The sinking STONE: what a failed validation can teach us about clinical decision rules.Ann Emerg Med. 2016; 67: 433-436Abstract Full Text Full Text PDF PubMed Scopus (8) Google Scholar and we refer interested readers to it for further information. Moore et al state that the STONE score outperformed physician gestalt; however, they fail to address our editorial comment that this statistical observation by Wang et al3Wang R.C. Rodriguez R.M. Moghadassi M. et al.External validation of the STONE score, a clinical prediction rule for ureteral stone: an observational multi-institutional study.Ann Emerg Med. 2016; 67: 423-432Abstract Full Text Full Text PDF PubMed Scopus (42) Google Scholar was on a modest margin likely below the threshold of clinical importance, and that it lies in a direction with doubtful potential to reduce imaging.1Green S.M. Schriger D.L. The sinking STONE: what a failed validation can teach us about clinical decision rules.Ann Emerg Med. 2016; 67: 433-436Abstract Full Text Full Text PDF PubMed Scopus (8) Google Scholar Moore et al inaccurately claim in their letter that the STONE score, when high, is accurate enough to defer computed tomography (CT) scanning. In their original study, they were far more cautious, citing the need for “future investigations” to assess “our hope…that this score can be incorporated into imaging decisions.”4Moore C.L. Daniels B. Luty S. et al.Derivation and validation of a clinical prediction rule for uncomplicated ureteral stone—the STONE score: retrospective and prospective observational cohort studies.BMJ. 2014; 348: g2191Crossref PubMed Scopus (98) Google Scholar And in the current letter, they do not counter specific data from our editorial refuting this very application. The failed validation found that a high STONE score was just 53% sensitive and 87% specific, ie, it would identify barely half of the patients with stones while diagnosing 13% of nonstone patients as falsely having calculi.1Green S.M. Schriger D.L. The sinking STONE: what a failed validation can teach us about clinical decision rules.Ann Emerg Med. 2016; 67: 433-436Abstract Full Text Full Text PDF PubMed Scopus (8) Google Scholar Thus, the STONE lacks sufficient accuracy to reliably rule in or rule out a stone, does not show potential as a clinically feasible tool to reduce CT scanning, and has demonstrated core rule infrastructure failure in a larger validation attempt. Although well intentioned, the score should be abandoned. The “Sinking” STONEAnnals of Emergency MedicineVol. 68Issue 1PreviewWe are pleased to see the attention that Annals has paid to the appropriate imaging for suspected renal colic. Full-Text PDF