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Validity of footprint analysis to determine flatfoot using clinical diagnosis as the gold standard in a random sample aged 40 years and older.

Pita-Fernández S, González-Martín C, Seoane-Pillado T, López-Calviño B, Pértega-Díaz S, Gil-Guillén V - J Epidemiol (2014)

Bottom Line: Multivariate regression was performed.Informed patient consent and ethical review approval were obtained.Sensitivity values were 89.8% for Clarke's angle, 94.2% for the Chippaux-Smirak index, and 81.8% for the Staheli index, with respective positive likelihood ratios or 9.7, 2.1, and 2.0.

View Article: PubMed Central - PubMed

Affiliation: Clinical Epidemiology and Biostatistics Research Group, Instituto de Investigación Biomédica de A Coruña (INIBIC), Complexo Hospitalario Universitario de A Coruña (CHUAC), SERGAS, Universidade da Coruña.

ABSTRACT

Background: Research is needed to determine the prevalence and variables associated with the diagnosis of flatfoot, and to evaluate the validity of three footprint analysis methods for diagnosing flatfoot, using clinical diagnosis as a benchmark.

Methods: We conducted a cross-sectional study of a population-based random sample ≥ 40 years old (n = 1002) in A Coruña, Spain. Anthropometric variables, Charlson's comorbidity score, and podiatric examination (including measurement of Clarke's angle, the Chippaux-Smirak index, and the Staheli index) were used for comparison with a clinical diagnosis method using a podoscope. Multivariate regression was performed. Informed patient consent and ethical review approval were obtained.

Results: Prevalence of flatfoot in the left and right footprint, measured using the podoscope, was 19.0% and 18.9%, respectively. Variables independently associated with flatfoot diagnosis were age (OR 1.07), female gender (OR 3.55) and BMI (OR 1.39). The area under the receiver operating characteristic curve (AUC) showed that Clarke's angle is highly accurate in predicting flatfoot (AUC 0.94), followed by the Chippaux-Smirak (AUC 0.83) and Staheli (AUC 0.80) indices. Sensitivity values were 89.8% for Clarke's angle, 94.2% for the Chippaux-Smirak index, and 81.8% for the Staheli index, with respective positive likelihood ratios or 9.7, 2.1, and 2.0.

Conclusions: Age, gender, and BMI were associated with a flatfoot diagnosis. The indices studied are suitable for diagnosing flatfoot in adults, especially Clarke's angle, which is highly accurate for flatfoot diagnosis in this population.

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Related in: MedlinePlus

Receiver operating characteristic curve for three kinds of footprint analyses to identify factors associated with flatfoot
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fig02: Receiver operating characteristic curve for three kinds of footprint analyses to identify factors associated with flatfoot

Mentions: The ROC curves for the methods of footprint analysis are displayed in Figure 2. The area under the curve shows that Clarke’s angle had high accuracy for predicting flatfoot (AUC 0.94), followed by the Chippaux-Smirak index (AUC 0.83) and the Staheli index (AUC 0.80), which were moderately accurate. The AUC of the Clarke’s angle was significantly different from that of the Chippaux-Smirak index and the Staheli index (Table 3). The Youden index, corresponding cut-off points, sensitivity, specificity, positive and negative predictive values, and positive and negative likelihood ratios, stratified by age group, are shown in Table 3. From the ROC curve, the optimal cut-off points of these tests for diagnosing flatfoot in the total sample were determined as follows: Clarke’s angle ≤30.5°, Chippaux-Smirak index ≥45.75%, Staheli index ≥0.825%, with sensitivities of 89.8%, 94.2%, and 81.8% respectively. The positive predictive values for Clarke’s angle, the Chippaux-Smirak index, and Staheli index were 69.5%, 33.5%, and 31.7% respectively. Respective negative predictive values were 97.4%, 97.6%, and 93.2%. Clarke’s angle was found to have the highest positive likelihood ratio (10.54).


Validity of footprint analysis to determine flatfoot using clinical diagnosis as the gold standard in a random sample aged 40 years and older.

Pita-Fernández S, González-Martín C, Seoane-Pillado T, López-Calviño B, Pértega-Díaz S, Gil-Guillén V - J Epidemiol (2014)

Receiver operating characteristic curve for three kinds of footprint analyses to identify factors associated with flatfoot
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4310876&req=5

fig02: Receiver operating characteristic curve for three kinds of footprint analyses to identify factors associated with flatfoot
Mentions: The ROC curves for the methods of footprint analysis are displayed in Figure 2. The area under the curve shows that Clarke’s angle had high accuracy for predicting flatfoot (AUC 0.94), followed by the Chippaux-Smirak index (AUC 0.83) and the Staheli index (AUC 0.80), which were moderately accurate. The AUC of the Clarke’s angle was significantly different from that of the Chippaux-Smirak index and the Staheli index (Table 3). The Youden index, corresponding cut-off points, sensitivity, specificity, positive and negative predictive values, and positive and negative likelihood ratios, stratified by age group, are shown in Table 3. From the ROC curve, the optimal cut-off points of these tests for diagnosing flatfoot in the total sample were determined as follows: Clarke’s angle ≤30.5°, Chippaux-Smirak index ≥45.75%, Staheli index ≥0.825%, with sensitivities of 89.8%, 94.2%, and 81.8% respectively. The positive predictive values for Clarke’s angle, the Chippaux-Smirak index, and Staheli index were 69.5%, 33.5%, and 31.7% respectively. Respective negative predictive values were 97.4%, 97.6%, and 93.2%. Clarke’s angle was found to have the highest positive likelihood ratio (10.54).

Bottom Line: Multivariate regression was performed.Informed patient consent and ethical review approval were obtained.Sensitivity values were 89.8% for Clarke's angle, 94.2% for the Chippaux-Smirak index, and 81.8% for the Staheli index, with respective positive likelihood ratios or 9.7, 2.1, and 2.0.

View Article: PubMed Central - PubMed

Affiliation: Clinical Epidemiology and Biostatistics Research Group, Instituto de Investigación Biomédica de A Coruña (INIBIC), Complexo Hospitalario Universitario de A Coruña (CHUAC), SERGAS, Universidade da Coruña.

ABSTRACT

Background: Research is needed to determine the prevalence and variables associated with the diagnosis of flatfoot, and to evaluate the validity of three footprint analysis methods for diagnosing flatfoot, using clinical diagnosis as a benchmark.

Methods: We conducted a cross-sectional study of a population-based random sample ≥ 40 years old (n = 1002) in A Coruña, Spain. Anthropometric variables, Charlson's comorbidity score, and podiatric examination (including measurement of Clarke's angle, the Chippaux-Smirak index, and the Staheli index) were used for comparison with a clinical diagnosis method using a podoscope. Multivariate regression was performed. Informed patient consent and ethical review approval were obtained.

Results: Prevalence of flatfoot in the left and right footprint, measured using the podoscope, was 19.0% and 18.9%, respectively. Variables independently associated with flatfoot diagnosis were age (OR 1.07), female gender (OR 3.55) and BMI (OR 1.39). The area under the receiver operating characteristic curve (AUC) showed that Clarke's angle is highly accurate in predicting flatfoot (AUC 0.94), followed by the Chippaux-Smirak (AUC 0.83) and Staheli (AUC 0.80) indices. Sensitivity values were 89.8% for Clarke's angle, 94.2% for the Chippaux-Smirak index, and 81.8% for the Staheli index, with respective positive likelihood ratios or 9.7, 2.1, and 2.0.

Conclusions: Age, gender, and BMI were associated with a flatfoot diagnosis. The indices studied are suitable for diagnosing flatfoot in adults, especially Clarke's angle, which is highly accurate for flatfoot diagnosis in this population.

Show MeSH
Related in: MedlinePlus