Tuberc Respir Dis.  2008 Feb;64(2):80-86.

Clinical Usefulness and the Accuracy of Korean Reference Equation for Diffusing Capacity

• Ra SW
• Park TS
• Hong Y
• Hong SB
• Shim TS
• Lim CM
• Lee SD
• Koh Y
• Kim WS
• Kim DS
• Kim WD
• Oh YM

Abstract

BACKGROUND: Park et al. developed the Korean reference equation for the measurement of diffusing capacity in 1985. However, the equation has not been widely used in Korea and foreign reference equations have been popularly used. We intended to compare the clinical usefulness and the accuracy of the the Korean reference equation (Park's equation) with that of the foreign equation (Burrows' equation) that is commonly used in Korea.
METHODS
1. Evaluation of clinical usefulness; Among 1,584 patients who underwent diffusing capacity (D(L)CO) at the Asan Medical Center from July to December 2006, group A subjects included 276 patients who had different interpretations of D(L)CO in trials employing Burrows' equation and Park's equation. Clinical assessment was decided by consensus of two respiratory physicians. In order to evaluate the clinical usefulness of Burrows' equation and Park's equation, agreement of clinical assessment and DLCO interpretation were measured. 2. Evaluation of accuracy; Group B subjects were 81 patients with interstitial lung disease (ILD) and 39 normal subjects. The 81 ILD patients were diagnosed following a surgical lung biopsy. The accuracy of diagnosing ILD as well as sensitivity and specificity were evaluated according to the use of the reference equations (Burrows' equation and Park's equation) for DLCO.
RESULTS
Agreement between clinical assessment and interpretation of D(L)CO was 22% for the use of Burrows' equation and 78% for the use of Park's equation. The sensitivity and specificity of the Burrows' equation for diagnosing ILD were 64.2% and 100%. The sensitivity and specificity of the Park's equation for diagnosing ILD were 90.1% and 100%. The sensitivity of the Park's equation for diagnosing ILD was significantly higher than that of Burrows' equation (p<0.001).
CONCLUSION
The Korean reference equation (Park's equation) was more clinically useful and had higher sensitivity for diagnosing ILD than the foreign reference equation (Burrows' equation).

Keyword

Diffusing capacity; Reference equations; Clinical usefulness; Accuracy

MeSH Terms

Biopsy
Consensus
Humans
Korea
Lung
Lung Diseases, Interstitial

Figure

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  Figure 1 Extraction of study subject group A. *Subjects those of less than 20 years old (743 subjects), non-Korean ethnicity (8 subjects), repeated cases (1,083 subjects), not doing diffusing capacity (7,548 subjects), and not doing lung volumes (507 subjects) were excluded. †Applying the Burrows' and the Park's equations using the lower limits of normal (LLN) by 95% confidence interval method to interpret PFT and to examine agreement between two equations. ‡Change of PFT interpretation by the Burrows' equation to the Park's. N → N: normal by the Burrows' equation → normal by the Park's equation; D → D: decrease by the Burrows' equation → decrease by the Park's equation; N → D: normal by the Burrows' equation → decrease by the Park's equation; D → N: decrease by the Burrows' equation → normal by the Park's equation.

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