INTRODUCTION
The World Health Organization (WHO) in 2016 reported that, the adult population with diabetes mellitus in 2014 amounted to 422 million in the world. According to Demographic and Family Health Survey 2016 (ENDES), type 2 diabetes mellitus is a public health problem at the national level. It is an issue due to its prevalence (3.2%), the high cost of treatment, and management of complications^1,2. Diabetic foot adds long hospital stays in contrast to any other complication of type 2 diabetes mellitus, with significant morbidity and mortality³.
The factors associated with diabetic foot are divided into two large groups which are non-modifiable, and modifiable. In this study the non-modifiable risk factors were analyzed: sex, age, and time of evolution of the disease greater than ten years. The modifiable factors such as glycosylated hemoglobin greater than 7.5%, history of smoking, onychomycosis, obesity, overweight, peripheral vascular disease, peripheral neuropathy, the presence of arterial hypertension, chronic kidney disease and dyslipidemia.
Diabetic foot, undoubtedly today, represents one of the most serious and frequent complications of diabetes mellitus 2. For this reason, it is important to determine the risk factors associated with diabetic foot in the PNP Luis N. Sáenz Hospital during the year 2017.
METHODS
Type and design of research
The research design of this study is observational, quantitative, retrospective, analytical type, of cases and controls. It was developed in the context of the IV COURSE - WORKSHOP OF GRADUATION BY THESIS according to the published and methodology approach⁴. Population and sample
Population and study sample included patients diagnosed with diabetes mellitus type 2 treated in the endocrinology division of the PNP Luis N. Sáenz Hospital during the months of January to December in 2017. The sample consisted of 165 patients: 55 cases diagnosed with diabetes mellitus type 2 as well as diabetic foot, and 110 controls with a diagnosis of diabetes mellitus type 2 without diabetic foot were the controls, with a ratio of 1: 2.
Data processing and analysis technique.
The "IMIN" calculator was used (IV COURSE - WORKSHOP OF GRADUATION BY THESIS ). Based on the bibliography review it was considered, an incidence of 9.8%, an odds ratio of 3.8, a level of statistical significance of less than 0.05%, and a range of 95% confidence.
The information was obtained from the medical records of the patient and recorded in a data collection sheet. The program IBM SPSS Statistics 25.0 was used to process them. Descriptive statistics, bivariate analysis (Chi-square and Odds ratio), and logistic regression of the variables of interest were performed.
RESULTS
The following variables were evaluated: sex, old age (over 60 years), body mass index (overweight, obesity), disease time over ten years, poor control (glycosylated hemoglobin > 7.5%), peripheral vascular disease, peripheral neuropathy, smoking history, onychomycosis, and comorbidities (arterial hypertension, chronic kidney disease, dyslipidemia).

Regarding the age of the patients according to age groups, the predominant group is the older adult (> = 60 years old) with 116 patients (70.3%), the other age group<60 years was made up of 49 patients (29.7%).In both sexes, the ages fluctuated between 60 and 80 years old and it was the male patients who had extreme ages. The minimum age was 32 years and the maximum age was 93 years. An average of 65.02 years was obtained, a mode of 69 years, and a median of 65 years. Regarding the sex variable, it was found the predominance of the masculine sex 91 (55.2%), in comparison to the feminine sex 74 (44.8%). Graphic 1

In the body mass index category, we found that of all patients, 131 (79.4%) had overweight and obesity type I, 92 patients with BMI between 25- 29.9 and 39 patients with BMI between 30-34.9, respectively. (Table1).

Of the non-modifiable risk factors, the disease with greater time than 10 years has 2.26 times more risk of developing diabetic foot, the association is statistically significant (p: 0.019, OR: 2.26, CI: 1.13- 4.52).nt (p: 0.019, OR: 2.26, CI: 1.13- 4.52).

The modifiable risk factors considered in this research study, glycosylated hemoglobin greater than 7.5% (poor control), onychomycosis, peripheral vascular disease, peripheral neuropathy, smoking history, obesity, overweight, chronic kidney disease, hypertension, and dyslipidemia are statistically associated with diabetic foot. (Table 3).
Patients who have dyslipidemia have 0.24 times more risk of developing diabetic foot, the association is statistically significant (p: 0.000), and because it presents an OR of 0.24 it behaves as a protection factor. It has a confidence interval of 0.11 - 0.48, that by not containing the unit it is statistically significant.

In Table 4, in the multivariate analysis it is observed that the time of disease (OR: 12.777, CI: 4.121-39.608, p: 0.000), glycosylated hemoglobin poorly controlled (OR: 4.551, IC: 1,171- 17,685, p: 0.029),Onychomycosis (OR: 7,108, CI: 1,483-34,074, p: 0.014), history of smoking (OR: 2666, CI: 1095-6349, p: 0.031 and chronic kidney disease as comorbidity (OR: 3.023, CI: 1.014- 9.013, p: 0.047) are significantly associated with diabetic foot.
DISCUSSION
In the present study it was found that the male sex did not have a significant association to diabetic foot (OR: 0.86, CI: 0.45 - 1.65, p: 0.65). This result is contradicted by the study of Mildred⁵, who reports that being male increases the risk of presenting diabetic foot (OR: 2, CI: 1.10 < OR < 3.72, p: 0.01528), this could be attributed to the fact that the sample of males was insufficient.
There was no significant association between the relation of advanced age, over 60 years old, and diabetic foot (OR: 0.63 IC: 0.30 - 1.33, p: 0.22). This result coincides with the study of Mildred⁵, who reported OR: 1.65, indicating a slight association, which was not supported by the CI: 0.84- 3.25 or by the p-value that was greater than 0.05. It is inferred that in both cases not enough necessary sample was taken to demonstrate this association.
The time of evolution of the disease, greater than 10 years, presented a significant association with the development of diabetic foot (OR: 2.26, CI 1.13 - 4.52, p: 0.019), presenting it as a risk factor for developing diabetic foot. This result coincides with the study by Márquez-Godínez⁶ (OR: 5.1, IC: 95% 2.8-9.4). In a study by Enciso⁷, a significant association between the time of evolution of the disease and the onset of diabetic foot was not corroborated (p: 0.5). Similar results were found in the study of Mildred⁵ in relationto the time of evolution of the disease, no association was found between the time elapsed since the diagnosis of diabetes and the presence of diabetic foot (OR: 0.96).
The percentage of glycosylated hemoglobin greater than 7.5%, as a margin of poor glycemic control, presented a significant association with diabetic foot (OR: 6.2, CI: 1.79 - 21.41, p: 0.001). However, in the Mildred⁵ study this association was corroborated (OR: 1.18, CI: 0.64 < OR 2.16, p: 0.569). Márquez-Godínez6, identified that glycosylated hemoglobin (HbA1c) ≥7.0% presents as a risk factor for developing diabetic foot (OR: 2.8, CI: 95% 1.5-5.0).
Peripheral vascular disease behaved like a risk factor for presenting diabetic foot (OR: 2.54, CI: 1.31 - 4.94, p: 0.005). In the study conducted by Flores⁸, this variable presented OR: 3.75, 95% CI 2.73- 5.15, p: 0.00, a risk factor with significant association. Similarly, in the study by Mildred⁵ a strong relationship with statistical significance could be established (OR: 13.62, CI: 6.23- 30.34, p<0.001).
Peripheral neuropathy behaved like a risk factor for the development of diabetic foot (OR: 2.88, CI:1.45 - 5.72 and p: 0.002). In the study by Mildred⁵, an important association was demonstrated between neuropathy and the presence of diabetic foot (CI <4.95 < OR 21.02 and p < 0.05). In the study by Neyra⁹, it was found as the main risk factor (OR of 71.8, p: <0.000) and in the Enciso⁷, study. This variable behaved like a risk factor, although it was not statistically significant (OR: 2.3, CI: 95% 0.7-7.4, p: 0.2).
Patients with onychomycosis have 4.83 times more risk of developing diabetic foot, finding OR: 4.83, CI: 1.38 - 16.86 and p:0.007. This result is supported in the study by Enciso⁷, which showed a strong association between the presence of onychomycosis, and the possibility of triggering diabetic foot (OR: 2.8, CI: 95% 1.1- 7.2, p: 0.02).
Smoking history behaved as a significantly associated risk factor (OR: 3.09, CI: 1.47 - 6.50, p: 0.002). In the study carried out by Flores⁸, the smoking habit was tested as a risk factor associated with diabetic foot, finding OR: 3.27, CI: 95% 1.27-8.39 and p: 0.01, being significantly associated.
With regard to comorbidities as an associated risk factor for diabetic foot, it was found that arterial hypertension and chronic kidney disease are significantly associated, OR: 2.13, CI: 1.08- 4.19, p: 0.027 and OR: 3.35, CI: 1.56 - 7.20, p: 0.0021, respectively. The dyslipidemia comorbidity behaved as a protective factor with the development of diabetic foot, presenting OR: O.24, CI: 0.11- 0.48 and p: 0.000. In the Chinchari study¹⁰, arterial hypertension (p: 0.29) and dyslipidemia (p: 0.12), did not present significant differences to be considered a risk factor.
In the study by Neyra⁹, it was found that arterial hypertension behaved as a protective factor, finding a significant association (OR: 0.1, p: 0.0025).
CONCLUSION
Disease time greater than ten years is a non-modifiable risk factor associated with diabetic foot. In addition, glycosylated hemoglobin greater than 7.5% (poorly controlled), onychomycosis, a history of smoking, and comorbid chronic kidney disease are modifiable risk factors associated with diabetic foot.
Peripheral vascular disease, peripheral neuropathy, hypertension are not modifiable risk factors associated with diabetic foot.

Authorship contributions: The authors involved in the generation, drafting and final approval of the article alsoYAE in data collection.

Financing: Self-financed.

Conflict of interest: The authors declare no conflict of interest in the publication of this article.

Received: December 27, 2018.

Approved: February 15, 2019.