Does this patient have clubbing?

Context The association between digital clubbing and a host of diseases has been recognized since the time of Hippocrates. Although the features of ad vanced clubbing are familiar to most clinicians, the presence of early club bing is often a source of debate. Objective To perform a systematic review of the literature for information on the precision and accuracy of clinical examination for clubbing. Data Sources The MEDLINE database from January 1966 to April 1999 was searc hed for English-language articles related to clubbing. Bibliographies of al l retrieved articles and of standard textbooks of physical diagnosis were a lso searched. Study Selection Studies selected for data extraction were those in which qu antitative or qualitative assessment for clubbing was described in a series of patients, Sixteen studies met these criteria and were included in the f inal analysis. Data Extraction Data were extracted by both authors, who independently revi ewed and appraised the quality of each article. Data extracted included qua ntitative indices for distinguishing clubbed from normal digits, precision of clinical examination for clubbing, and accuracy of clubbing as a marker of selected diseases. Data Synthesis The profile angle, hyponychial angle, and phalangeal depth r atio can be used as quantitative indices to assist in identifying clubbing. In individuals without clubbing, values for these indices do not exceed 17 6 degrees, 192 degrees, and 1.0, respectively. When clinicians make a globa l assessment of clubbing at the bedside, interobserver agreement is variabl e, with kappa values ranging between 0.39 and 0.90. Because of the lack of an objective diagnostic criterion standard, accuracy of physical examinatio n for clubbing is difficult to determine. The accuracy of clubbing as a mar ker of specific underlying disease has been determined for lung cancer (lik elihood ratio, 3.9 with phalangeal depth ratio in excess of 1.0) and for in flammatory bowel disease (likelihood ratio, 2.8 and 3.7 for active Crohn di sease and ulcerative colitis, respectively, if clubbing is present). Conclusions We recommend use of the profile angle and phalangeal depth rati o as quantitative indices in identifying clubbing. Clinical judgment must b e exercised in determining the extent of further evaluation for underlying disease when these values exceed 180 degrees and 1.0, respectively.