Type 2 diabetes mellitus is a growing affection with an epidemic trend that became a public health concern problem worldwide, particularly in developing countries where the estimated progression is higher than in de- veloped countries [1] . In Benin republic, the nationwide prevalence estimated to 1.1% in 2001 grows up to 2.6% in 2008 [2] [3] confirming the worldwide epidemic trend reported by King and Rewers in 1993 and Wild in 2004 [4] [5] . The costly aspect of the affection reside in the long term complications which are also sources of over morbidity and mortality in diabetic patients. Knowledge of factors associated with these complications can help to prevent them.

The objectives of the present study are to determine the rate of long term complications in the type 2 diabetic patients followed up in the diabetic center in Cotonou and to identify factors associated to these complications.

Study population consisted in type 2 diabetic patients from 25 to 64 years old attending the diabetes center. The sampling was constituted by exhaustive sounding of successive diabetic patients received during the study period. With their own consent, patients were submitted to a questionnaire and to a clinical examination. Data were completed by consulting medical reports of patients. Data collection concerned socio-demographic cha- racteristics of patients and long term complications. Complications investigated were:

1) Peripheral neuropathy, based on the presence of subjective man if estations as paresthesia, burning feet, and the abolition of bone reflexes at the clinical examination;

2) Erectile dysfunction;

3) Nephropathy, based on the presence of proteinuria in the absence of other causes of proteinuria;

4) Macroangiopathy, based on the presence of legs arteries disease or ischemic cardiac disease;

5) Retinopathy, based on the presence of specific lesions at the fundoscopy;

6) Data on macroangiopathy were available for only 30 patients and on retinopathy for only 50 patients;

7) Statistical analysis was made using the Chi square test;

8) Research protocol was approved by the Review Board of the Institut Régional de Santé Publique.

A total of 150 patients were included in this study comprising 93 women (62%) and 57 men. The mean age of patients was 55 ± 10 years.

Out of these 150 patients, 117 presented at least one of the investigated complications meaning a prevalence rate of 78.0%. The specific prevalence rate of each complication is summarized in Table 1.

As it appears in this table, the more prevalent complication observed is neuropathy and three out of four type 2 diabetic men complained of erectile dysfunction.

Study of factors associated with chronic complications in diabetic patients is shown in Table 2 and Table 3.

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As shown in Table 2, complication rate was significantly higher in men than in women and type 2 diabetic patients of 50 years or more old showed higher complication rate. Another factor associated with the high com- plication rate was the patient’s own perception of the disease. The high rate of complication was also associated with hypertension, the absence of familial history of diabetes, the duration of diabetes and the high plasma level of glycated haemoglobin (Table 3).

The global complication rate of 78% revealed by this study is very high since other studies conducted in other countries of the sub-Saharan Africa region have shown lower complication rates of 58% [6] and 65% [7] . As the study population has not been randomly selected, this higher complication rate can be explained by the fact that the center where the study has been conducted is a specialized center for diabetes care and can concentrate di- abetic patients with particular health problems.

Mean age of patients of 55 ± 10 years observed in our study is similar to what had been reported by Belkhadir et al. [8] and closed to 52 years reported by Touré in Mali [9] but lower than 62 years reported in France [10] , showing that in developing countries, diabetes and its complications appear in a younger age than in developed countries.

When specific complications are considered, we can notice that the rate of neuropathy observed in our study is higher than the rate of 45% reported by Ouerdane et al. [11] but less high than the rate of 80% observed by Fendi et al. [12] evaluating diabetic neuropathy by the DN4 score. Our rate of neuropathy is conform to results reported by the Diabcare Africa Study with rate of neuropathy ranging from 39.19% to 63.70% in different Africa regions [13] .

Regarding nephropathy based on proteinuria, the rate of 8.9% reported by Läcätusu et al. [14] is lower than what we found in our study. In a previous study a lower rate has also been reported in Cotonou [15] . Kabaj et al. reported a rate of 53.85% of nephropathy in type 2 diabetic patients in Maroco [16] .

Investigation of retinopathy revealed a rate of 36.0% which is less high than the rate of 47.5% reported by Khadraoui et al. [17] in Tunisia but closed to 36.6% reported by Tchabi et al. [18] in the north of Benin. In the 150 patients included in our study, only 50 were investigated for retinopathy. This confirms the observation of Rosenberg et al. who reported in their study that only 35% of studied patients were referred for eye exam show- ing that screening guidelines for diabetic retinopathy are not often respected by physician [19] .

In this study, high global complication rate was associated with several factors in which patients’ age and the male gender can be underlined. Another factor significantly associated with the high rate of complications is the perception the patients have of the disease. Those with bad perception of the disease often considered diabetes mellitus as a traditionally induced disease and then spend a long time with traditional healers before attending hospital. This behavior can explain the high rate of complications in relation of a long period of uncontrolled disease.

Factors classically associated with high rate of complications in type2 diabetes such as patients’ age, the dura- tion of the disease, the presence of hypertension and high HbA₁c level have been evidenced in our study. No association was found between complication rate and obesity.

It can be noticed that patients without familial history of diabetes presented significantly higher rate of com- plications suggesting that those with familial history of diabetes are more prone to better care of their condition than the others.

This study has shown a high prevalence of long term complications in type 2 diabetic patients attending the di- abetic center. It is now well known that the good control of the disease is associated with reduced complications. As the presence of these complications is also associated with the duration of the disease, the challenge must be precocious diagnosis and tight control of diabetes.