Journal of Indian Academy of Oral Medicine and Radiology

: 2018  |  Volume : 30  |  Issue : 3  |  Page : 241--246

“Frank Sign” – A clinical indicator in the detection of coronary heart disease among dental patients: A case control study

Praveenkumar Ramdurg1, Naveen Srinivas1, Surekha Puranik1, Abhijeet Sande2,  
1 Department of Oral Medicine and Radiology, PMNM Dental College and Hospital, Bagalkot, Karnataka, India
2 Department of Oral Medicine and Radiology, School of Dental Sciences, KIMS, Karad, Karnataka, India

Correspondence Address:
Dr. Naveen Srinivas
Department of Oral Medicine and Radiology PMNM Dental College and Hospital, Bagalkot - 587 101, Karnataka


Background: The diagonal earlobe crease (DELC) has been proposed to be a marker of coronary heart disease (CHD), but this association remains controversial. Data available in Indian population seeking dental treatment are limited. Objective: The aim of this study was to evaluate the association between DELC and CHD. Methods: This case–control study investigated 118 cases with CHD and 50 controls without CHD. Characteristic differences and the relation of DELC to CHD were assessed by Chi-square and Student's t-tests. Multivariate logistic regression analysis was done to estimate the risk of various factors between cases and control. Results: The prevalence of DELC was 63.21% in cases and 26.79% in controls (<0.001). There was a significant correlation between DELC and coronary risk factors, such as advancing age, hypertension, male gender, and no correlation among DELC, diabetes mellitus, hyperlipidemia, and smoking. Conclusion: The association between DELC and CHD patients was high in our study. The data suggest that the DELC sign may be a useful marker for early detection of CHD in dental patients.

How to cite this article:
Ramdurg P, Srinivas N, Puranik S, Sande A. “Frank Sign” – A clinical indicator in the detection of coronary heart disease among dental patients: A case control study.J Indian Acad Oral Med Radiol 2018;30:241-246

How to cite this URL:
Ramdurg P, Srinivas N, Puranik S, Sande A. “Frank Sign” – A clinical indicator in the detection of coronary heart disease among dental patients: A case control study. J Indian Acad Oral Med Radiol [serial online] 2018 [cited 2021 Nov 30 ];30:241-246
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Coronary heart disease (CHD) is the foremost cause of death worldwide; its deterrence is a public health prime concern.[1] More than 75% of these deaths occurred in developing countries. In contrast to developed countries, where mortality from CHD is rapidly declining.[2] As more than 1.3 billion people live in India,[3] the morbidity and mortality of CHD have been growing since the past 30 years. In India, more than 10.5 million deaths occur annually, and it was reported that CHD led to 20.3% of these deaths in men and 16.9% of all deaths in women.[4] It is highly critical to explore the usefulness of various simple and reliable signs of atherosclerosis with respect to identification of the participants at risk for CHD to decrease the liability inflicted by the disease.

The diagonal ear lobe crease (DELC) or “Frank's sign” has long been recognized as a potential marker of CHD. Despite its identification over 40 years ago, very few oral care providers are aware of the relevance of Frank's sign as a cutaneous indicator of coronary atherosclerosis. The presence of DELC and its association with CHD were first described in 1973.[5]

Since Frank's original study, several clinical studies,[6],[7],[8],[9] including autopsy-based[10] and histopathological examinations,[11] have shown an association between DELC and CHD and support the hypothesis that DELC was related to CHD. The DELC is useful as a “sign” for CHD because it can be seen at a glance. On the contrary, several studies reported negative results and suggest that it is simply a marker of advancing age[12],[13],[14] and the lack of a theoretical foundation for a causal relationship between DELC and atherosclerosis inhibits the clinical value.

Hence, in this study, we aim to highlight evidence linking DELC with CHD. We would like to emphasize that this easily identifiable yet routinely missed sign provides a valuable contribution to the dentist in his assessment of patients at risk of ischemic heart disease in dental office.

To our knowledge, this is the first study aimed to find out the association between DELC in CHD patients who visited dentist for various dental treatments.

 Materials and Methods

The present study was designed as a case–control study. Subjects were recruited from the department of oral medicine and radiology who visited for various dental treatments. A total of 118 patients aged >40 years with proven CHD (who had undergone angiography and were found to have CHD) and 50 patients without evidence of CHD of same age group were enrolled in this study. This study was approved by the institutional ethics committee. All participants gave written informed consent.

Routine preoperative evaluation included taking a history and routine examination. Blood pressure was measured on several occasions during dental visits and hypertension was defined as systolic blood pressure ≥140 mm Hg or diastolic blood pressure ≥90 mm Hg; or use of antihypertensive medications. Patients on lipid-lowering drugs or abnormal lipid profile were classified as having hyperlipidemia, and patients with elevated serum glucose level or on treatment for diabetes were considered as diabetes. The participants' smoking status was classified as either “not smoking” or “smoking.”

A modified evaluation sheet designed by Shrestha[15] was used to assess the DELCs. A deep diagonal crease (>1 mm) extending obliquely from the tragus toward the outer border of the ear lobe and covering at least two-thirds of the length of the ear lobe was recorded as a DELC. Unilateral and bilateral DELCs were both considered to be DELC positive [Figure 1] and [Figure 2]. Patients who showed an incomplete pattern of DELC, in which a diagnosis of the DELC might be confused, were excluded from the study. All the patients were examined in sitting position.{Figure 1}{Figure 2}

Statistical analysis

Data were expressed as mean ± standard deviation. Comparison of the categorical or numeric variables between groups was carried out using a Chi-square test or Student's t-test separately. The multivariate regression model was used to rule out possible mutual association of traditional risk factors (including age, sex, cigarette smoking, hypertension, hyperlipidemia, and diabetes mellitus) with cases and control groups. The sensitivity, specificity, and predictive values of DELC in two genders and four age groups (40–50, 51–60, 61–70, and >70 years old) were computed. A P value of <0.05 was regarded as being statistically significant. All statistical analysis was conducted using Statistical Package for Social Sciences [SPSS] for Windows Version 22.0 Released 2013. Armonk, NY: IBM Corp.


The demographic and clinical characteristics of 118 cases and 50 controls are shown in [Table 1]. Total participants (cases and controls) were classified into four age groups (40–50, 51–60, 61–70, and >70 years). The mean age and standard deviation of the cases and controls were 61.25 ± 0.92 (95% confidence interval: 59.44–63.06) and 53.81 ± 1.39 (95% confidence interval: 51.08–56.55), respectively. This difference was statistically significant (<0.001) in cases and controls with different age group. The prevalence of DELC was 63.21% in cases and 26.79% in controls [Graph 1] and [Graph 2] which was statistically significant (<0.001). In the group with CHD (cases), hypertension was in 82.18%, diabetes mellitus in 69.54%, hyperlipidemia in 41.44%, and smoking in 40.04%. In controls, hypertension was in 34.81%, diabetes mellitus in 29.46%, hyperlipidemia in 17.56%, and smoking in 16.96%. There were no statistical significant results found between these comorbidities except smoking, which was statistically significant (<0.001).{Table 1}[INLINE:1][INLINE:2]

On comparison of clinical characteristics among cases, statistically significant results (<0.001) were found in gender, different age group, and smoking between subjects with and without DELC [Table 2], whereas among controls, statistically significant results (0.001) were found only in different age groups and smoking between subjects with and without DELC [Table 3].{Table 2}{Table 3}

There was a significant correlation between DELC and coronary risk factors, such as advancing age, hypertension, male gender, and no correlation among DELC, diabetes mellitus, hyperlipidemia, and smoking. DELC was significantly related to CHD as an independent variable by logistic regression analysis [Table 4].{Table 4}

The sensitivity and specificity for DELC to predict CHD is 90 and 52.51%, respectively, whereas positive predictive value (PPV) is 68.64% and negative predictive value (NPV) is 82%. Accuracy of DELC to predict CHD is 72.62% [Table 5].{Table 5}


Since the first report of DELC by Frank in 1973,[5] various studies have found varying degrees of association between DELC and CHD as reviewed by Friedlander.[7] Several investigations indicated the DELC as a marker of CHD and generalized atherosclerotic disease.[16],[17],[18],[19],[20],[21] However, this association still remain disputable due to the confounding effects of age and sex and the different parameters used for diagnosis of CHD. Over the past 35 years there have been a number of published studies that have failed to substantiate the relationship between DELC and CHD.[22],[23],[24],[25],[26]

In the 1970s and 1980s, it was postulated that DELC and CHD exist concurrently because the earlobe and heart are supplied by “end arteries” without the possibility for collateral circulation.[27] Others suggested that the generalized loss and degeneration of elastic fibers seen in biopsy specimens taken from the earlobes of patients affected with CHD reflected the microvascular disease that was also present in the coronary bed.[28]

The current study showed that the prevalence of DELC was high in patients with CHD (63.21%) compared with controls (26.79%). The study conducted by Raman[29] showed that the DELC was observed in nearly 60% of the urban south Indian population. In Australia, Davis et al.[30] reported that the prevalence of DELC was 55% in CHD patients. A study by Edston[10] on autopsy cases, the existence of a DELC was noted in 55%. These results are consistent with present study. It was found that DELC was strongly correlated with CHD in both men and women.

In our research, we studied the association between DELC and CHD proven with coronary angiography; therefore, clinical criteria for the diagnosis of CHD were not used. Our study outcome denotes that the prevalence of DELC and CHD increases with increasing age. We also found that DELC was significantly related with major coronary risk factors such as hypertension, male gender, cigarette smoking, and age while it had no relation with diabetes mellitus, and hyperlipidemia. Tranchesi et al.[31] reported results similar to ours, that is, patients with DELC, irrespective of age or sex, have a significantly increased prevalence of CHD. Present results were in contrast to the report of Kuon et al.[14] who reported that while the DELC was associated with age and increased body mass index, it did not predict CHD. These differences may be associated with genetic factors and racial differences.

When hypertension was taken into consideration, our study support the positive correlation result obtained by others.[32],[33] However, it is inconsistent with other studies[34] who failed to find associations between cardiovascular risk factors including hypertension and earlobe in CHD patients. As for diabetes mellitus and hyperlipidemia were concerned, a Japanese study[35] suggested a strong correlation with CHD. But our study shows no relation which is in accordance with others.[18],[36]

We observed sensitivity, specificity, PPV, and NPV of the DELC for diagnosis of CHD and they were in the following order: 90, 52.5, 68.64, and 82%, respectively. Our results were not similar to previous studies.[37],[38],[39] This may be related to the study population and criteria that were used to define the presence of DELC in this study. Previous studies have defined the depth of crease, whereas we did not, this may (might) have led to an overestimate of the number of patients with the DELC sign. This would result in reduction in the PPV of the sign. However, in emergency situation, it may be better to overestimate the incidence of CHD. Therefore, high sensitivity may be clinically important, even if this leads to false-negative results of the test.

Limitation of the study

We would like to state that with solely one ethnic population, relatively small sample size, and single center design in this study, the result may not be generalized. Therefore, we suggest more longitudinal studies on large samples in both academic and nonacademic hospitals. Furthermore, there is no information provided about the extent and severity of coronary disease.


The vast majority of the medical literature supports the association between DELC and CHD; however, in this article, we have also given voice to some research findings. We observed a significantly increased prevalence of DELC in patients with CHD regardless of the other coronary risk factors. DELC might be an independent variable for CHD, and the prevalence of DELC and CHD increases with advancing age. We also observed that DELC was significantly correlated with the major coronary risk factors. We believe that this easily detectable sign could be useful in dental practice, helping the dental surgeon to add new and valuable information to the patient's risk profile.

Financial support and sponsorship


Conflicts of interest

There are no conflicts of interest.


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