Rat bite as a cause of diabetic foot ulcer in sub-Saharan Africa.

There have been relatively few reports of foot ulcers in diabetes resulting from rat bite. The findings were derived from people attending a single specialist service in Dar es Salaam for diabetic foot ulcers (DFUs) between 1 January 1999 and 31 December 2016. Details from people presenting for the first time with an ulcer judged to be caused by rat bite were compared with those with from other causes of foot ulcer. There were 426 first recorded foot ulcer episodes (in 179 people) judged to be caused by rat bite. The affected population was significantly younger (mean 55.9 vs 57.5 years, P = .037) and had a lower body mass index (26.5 vs 27.9, P = .008) than controls with other types of foot ulcer. They also presented significantly sooner (7.8 vs 18.2 days, P < .001) and were more likely to heal (85.8 vs 5.5%, P < .001), even though there was also a trend towards an increased risk of death (9.1% vs 5.3%, P = .032). Rat bite is an uncommon cause of DFU, but is not rare. Although the incidence of ulcer healing is higher than in a general foot ulcer population, the incidence of death is also higher.

What characteristics are most important in stratifying patients into groups with different risk of diabetic foot ulceration?

AIMS/INTRODUCTION: This study aimed to assess if patients can be divided into different strata, and to explore if these correspond to the risk of diabetic foot complications. MATERIALS AND METHODS: A set of 28 demographic, vascular, neurological and biomechanical measures from 2,284 (1,310 men, 974 women) patients were included in this study. A two-step cluster analysis technique  was utilised to divide the patients into groups, each with similar characteristics. RESULTS: Only two distinct groups: group 1 (n = 1,199; 669 men, 530 women) and group 2 (n = 1,072; 636 men, 436 women) were identified. From continuous variables, the most important predictors of grouping were: ankle vibration perception threshold (16.9 ± 4.1 V vs 31.9 ± 7.4 V); hallux vibration perception threshold (16.1 ± 4.7 V vs 33.1 ± 7.9 V); knee vibration perception threshold (18.2 ± 5.1 V vs 30.1 ± 6.5 V); average temperature sensation threshold to cold (29.2 ± 1.1°C vs 26.7 ± 0.7°C) and hot (35.4 ± 1.8°C vs 39.5 ± 1.0°C) stimuli, and average temperature tolerance threshold to hot stimuli at the foot (43.4 ± 0.9°C vs 46.6 ± 1.3°C). From categorical variables, only impaired sensation to touch was found to have importance at the highest levels: 87.4% of those with normal sensation were in group 1; whereas group 2 comprised 95.1%, 99.3% and 90.5% of those with decreased, highly-decreased and absent sensation to touch, respectively. In addition, neuropathy (monofilament) was a moderately important predictor (importance level 0.52) of grouping with 26.2% of participants with neuropathy in group 1 versus 73.5% of participants with neuropathy in group 2. Ulceration during follow up was almost fivefold higher in group 2 versus group 1. CONCLUSIONS: Impaired sensations to temperature, vibration and touch were shown to be the strongest factors in stratifying patients into two groups with one group having almost 5-fold risk of future foot ulceration compared to the other.

The utility of Gram stains and culture in the management of limb ulcers in persons with diabetes.

In Tanzania, limited laboratory services often preclude routine identification of microorganisms that cause infections in persons with diabetes. Thus, we carried out this study to determine the utility of a Gram stain alone versus culture in guiding appropriate antimicrobial therapy. During February 2006 to December 2007 (study period), deep tissue biopsies were obtained from persons with diabetes presenting to the Muhimbili National Hospital (MNH) with infected limb ulcers. Specimens were Gram-stained then cultured for bacteria and fungi. Biopsies were obtained from 128 patients. Of 128 cultures, 118 (92%) yielded bacterial or fungal growth; 59 (50%) of these 118 cultures yielded mixed growth (80% included Gram-negative organisms); 38 (32%) and 20 (17%) yielded Gram-negative and Gram-positive organisms alone, respectively. The predictive value positive of a Gram stain for bacterial growth was 93% (110/118); a Gram-positive stain was 75% (15/20) predictive of growth of Gram-positive organisms whereas a Gram-negative stain was 82% (31/38) predictive of growth of Gram-negative organisms. In regions with limited resources, a Gram stain of an ulcer biopsy that is carefully procured is largely predictive of the type of microorganism causing infection. Gram staining of deep tissue biopsies might have a potential role to play in the management of infected diabetic limb ulcers.

Predicting the risk of amputation and death in patients with diabetic foot ulcer. A long-term prospective cohort study of patients in Tanzania.

INTRODUCTION: This prospective cohort study aimed to identify the characteristics of patients with diabetic foot ulcer who are at higher risk of amputation and at increased risk of death. METHODS: About 103(M/F:60/43) participants, with active foot ulcer at baseline, participated in this study and followed for 22 years till death or lost to follow-up. Ten clinical measures were collected at baseline. During the follow-up of 4.2 ± 5.4 years, 22(M/F:14/8) participants had an amputation and 50(M/F:32/18) participants passed away during 5.5 ± 5.8 years follow-up period. RESULTS: Cox Proportional Hazard regression (HR[95%CI]) indicated neuropathy (6.415[1.119-36.778]); peripheral arterial disease (PAD) (9.741[1.932- 49.109]); current smoking (16.148[1.658-157.308]); diabetes type- 1 (3.228[1.151-9.048]) and longer delay attending appointment after ulcer (1.013[1.003-1.023]) were significantly (p < .05) associated with increased risk of amputation. In addition, death was significantly associated with the risk of amputation (3.458[1.243-9.621]). Three parameters (HR[95%CI]) including neuropathy (3.058[1.297-7.210]); PAD (5.069[2.113-12.160]); amputation history (3.689[1.306-10.423]) and retinopathy (2.389[1.227-4.653]) were all significantly associated with increased risk of death. Kaplan-Meier survival analyses indicates that the time to amputation in years for participants who eventually died was significantly shorter (11.122 ± 1.507) vs those who stayed alive (15.427 ± 1.370). CONCLUSION: Neuropathy and PAD were the only two characteristics that increased both the risk of amputation and death. Amputation showed to contribute to an increased risk of death and those participants who eventually died had a higher risk of amputation. Delay in attending appointments after ulceration is shown to increase the risk of amputation. In addition, the participants with PAD showed a significantly shorter time to both amputation and death while neuropathy was only associated with decreased time to death. Amputation history and death during follow-up decrease the time to death and amputation respectively.

The 'Step by Step' Diabetic Foot Project in Tanzania: a model for improving patient outcomes in less-developed countries.

Foot complications cause substantial morbidity in Tanzania, where 70% of leg amputations occur in diabetic patients. The Step by Step Foot Project was initiated to train healthcare personnel in diabetic foot management, facilitate transfer of knowledge and expertise, and improve patient education. The project comprised a 3-day basic course with an interim period 1-year of for screening, followed by an advanced course and evaluation of activities. Fifteen centres from across Tanzania participated during 2004-2006 and 12 during 2004-2007. Of 11,714 patients screened in 2005, 4335 (37%) had high-risk feet. Of 461 (11%) with ulcers, 45 (9·8%) underwent major amputation. Of 3860 patients screened during 2006-2007, there was a significant increase in the proportion with ulcers and amputations compared with 2005 (P < 0·001), likely a result of enhanced case finding. During 2005-2008, there was a fall in the incidence of foot ulcers in patient referrals to the main tertiary care centre in Dar es Salaam and a parallel fall in amputation among these referrals. In conclusion, the Step by Step Foot Project in Tanzania improved foot ulcer management for persons with diabetes and resulted in permanent, operational foot clinics across the country. This programme is an effective model for improving outcomes in other less-developed countries.

Predicting the risk of future diabetic foot ulcer occurrence: a prospective cohort study of patients with diabetes in Tanzania.

OBJECTIVES: The aim of this study was to identify the parameters that predict the risk of future foot ulcer occurrence in patients with diabetes. RESEARCH DESIGN AND METHODS: 1810 (male (M)/female (F): 1012/798) patients, with no foot ulcer at baseline, participated in this study. Data from a set of 28 parameters were collected at baseline. During follow-up, 123 (M/F: 68/55) patients ulcerated. Survival analyses together with logistic regression were used to identify the parameters that could predict the risk of future diabetic foot ulcer occurrence. RESULTS: A number of parameters (HR (95% CI)) including neuropathy (2.525 (1.680 to 3.795)); history of ulceration (2.796 (1.029 to 7.598)); smoking history (1.686 (1.097 to 2.592)); presence of callus (1.474 (0.999 to 2.174)); nail ingrowth (5.653 (2.078 to 15.379)); foot swelling (3.345 (1.799 to 6.218)); dry skin (1.926 (1.273 to 2.914)); limited ankle (1.662 (1.365 to 2.022)) and metatarsophalangeal (MTP) joint (2.745 (1.853 to 4.067)) ranges of motion; and decreased (3.141 (2.102 to 4.693)), highly decreased (5.263 (1.266 to 21.878)), and absent (9.671 (5.179 to 18.059)) sensation to touch; age (1.026 (1.010 to 1.042)); vibration perception threshold (1.079 (1.060 to 1.099)); duration of diabetes (1.000 (1.000 to 1.000)); and plantar pressure at the first metatarsal head (1.003 (1.001 to 1.005)), temperature sensation (1.019 (1.004 to 1.035)) and temperature tolerance (1.523 (1.337 to 1.734)) thresholds to hot stimuli and blood sugar level (1.027 (1.006 to 1.048)) were all significantly associated with increased risk of ulceration. However, plantar pressure underneath the fifth toe (0.990 (0.983 to 0.998)) and temperature sensation (0.755 (0.688 to 0.829)) and temperature tolerance (0.668 (0.592 to 0.0754)) thresholds to cold stimuli showed to significantly decrease the risk of future ulcer occurrence. Multivariate survival model indicated that nail ingrowth (4.42 (1.38 to 14.07)); vibration perception threshold (1.07 (1.04 to 1.09)); dry skin status (4.48 (1.80 to 11.14)); and temperature tolerance threshold to warm stimuli (1.001 (1.000 to 1.002)) were significant predictors of foot ulceration risk in the final model. The mean time to ulceration was significantly (p<0.05) shorter for patients with: dry skin (χ2=11.015), nail ingrowth (χ2=14.688), neuropathy (χ2=21.284), or foot swelling (χ2=16.428). CONCLUSION: Nail ingrowth and dry skin were found to be strong indicators of vulnerability of patients to diabetic foot ulceration. Results highlight that assessments of neuropathy in relation to both small and larger fiber impairment need to be considered for predicting the risk of diabetic foot ulceration.

Diabetic foot ulcers and ethnicity in Tanzania: a contrast between African and Asian populations.

To characterise the role of ethnicity in the occurrence of foot ulcer disease in persons with diabetes, we analysed prospectively collected data for persons attending the diabetes clinic at Muhimbili National Hospital (MNH), Dar es Salaam, Tanzania. A case was defined as any adult presenting to MNH with an ulcer at or below the ankle joint during July 1998-June 2005. We documented clinical and epidemiologic characteristics, progress, interventions and outcome. Seven hundred and eight persons met the case definition - 570 (80%) ethnic Africans and 138 (20%) Asian Indians. Ethnic Africans were more likely to present with gangrene (P < 0.01); Indians were more likely to be obese (P < 0.001) or have large vessel disease (P < 0.001). For Africans, intrinsic complications (neuro-ischaemia or macrovascular disease) delayed ulcer healing; for Asian Indians, mode of intervention (e.g. sloughectomy or glycaemic control with insulin or oral agents) determined the same outcome. Indigenous ethnic African and Asian Indian populations with diabetes display contrasting foot ulcer epidemiology. Peripheral vascular disease and gangrene are playing a larger role in ulcer pathogenesis and outcomes for both ethnic groups than was previously thought. Preventive efforts and interventions should be tailored to the two ethnic groups to achieve complete ulcer healing.

Can a combination of lifestyle and clinical characteristics explain the presence of foot ulcer in patients with diabetes?

AIMS: The aim of this study was to identify the biomechanical, neurological and clinical parameters along with other demographics and lifestyle risk factors that could explain the presence of foot ulcer in patients with diabetes in Africa. METHODS: A total of 1270 (M/F:696/574) patients; 77(M/F:53/24) with ulcerated vs 1193 (M/F: 643/550) with non-ulcerated feet; participated in this study. A set of 28 parameters were collected and compared between the participants with and without active foot ulcers. Multivariate logistic regression was utilised to develop an explanatory model for foot ulceration. RESULTS: Foot swelling (χ2(1,n = 1270) = 265.9,P = 0.000,Phi = 0.464) and impaired sensation to monofilament (χ2(2,n = 1270) = 114.2,P = 0.000,Cramer'sV = 0.300) showed strong association with presence of ulceration. A lower Temperature sensitivity to cold stimuli and limited ankle joint mobility were observed to be significant (P < 0.05) contributors to ulceration. The logistic regression model can justify the presence of foot ulceration with 95.3% diagnostic accuracy, 99.1% specificity and 37.3% sensitivity. CONCLUSION: Participants with ulcerated foot show distinct characteristics in few foot related parameters. Swollen foot, limited ankle mobility, and peripheral sensory neuropathy were significant characteristics of patients with diabetic foot ulcer. One out of three patients with ulcerated foot showed common characteristics that could be justified by the model.

Use of the SINBAD classification system and score in comparing outcome of foot ulcer management on three continents.

OBJECTIVE: To compare populations with and outcomes of diabetic foot ulcers managed in the U.K., Germany, Tanzania, and Pakistan and to explore the use of a new score of ulcer type in comparing outcomes among different countries. RESEARCH DESIGN AND METHODS: Data from a series of 449 patients with diabetic foot ulcers managed in the U.K. were used to evaluate the new simplified system of classification and to derive an aggregate score. The use of the score was then explored using data from series managed in Germany (n = 239), Tanzania (n = 479), and Pakistan (n = 173). RESULTS: A highly significant difference was found in time to healing between ulcers of increasing score in the U.K. series (Kruskal-Wallis test; P = 0). When data from all centers were examined, a step-up in days to healing was noted for those with scores of >or=3 (out of 6). Examination of baseline variables contributing to outcome revealed the following differences among centers: ischemia, ulcer area, and depth contributing to outcome in the U.K.; ischemia, area, depth, and infection in Germany; depth, infection, and neuropathy in Tanzania; and depth alone in Pakistan. CONCLUSIONS: Any system of classification designed for general implementation must encompass all the variables that contribute to outcome in different communities. Adoption of a simple score based on these variables, the Site, Ischemia, Neuropathy, Bacterial Infection, and Depth (SINBAD) score, may prove useful in predicting ulcer outcome and enabling comparison among different centers.