Five year mortality and direct costs of care for people with diabetic foot complications are comparable to cancer

Abstract

Background

In 2007, we reported a summary of data comparing diabetic foot complications to cancer. The purpose of this brief report was to refresh this with the best available data as they currently exist. Since that time, more reports have emerged both on cancer mortality and mortality associated with diabetic foot ulcer (DFU), Charcot arthropathy, and diabetes-associated lower extremity amputation.

Methods

We collected data reporting 5-year mortality from studies published following 2007 and calculated a pooled mean. We evaluated data from DFU, Charcot arthropathy and lower extremity amputation. We dichotomized high and low amputation as proximal and distal to the ankle, respectively. This was compared with cancer mortality as reported by the American Cancer Society and the National Cancer Institute.

Results

Five year mortality for Charcot, DFU, minor and major amputations were 29.0, 30.5, 46.2 and 56.6%, respectively. This is compared to 9.0% for breast cancer and 80.0% for lung cancer. 5 year pooled mortality for all reported cancer was 31.0%.

Direct costs of care for diabetes in general was $237 billion in 2017. This is compared to $80 billion for cancer in 2015. As up to one-third of the direct costs of care for diabetes may be attributed to the lower extremity, these are also readily comparable.

Conclusion

Diabetic lower extremity complications remain enormously burdensome. Most notably, DFU and LEA appear to be more than just a marker of poor health. They are independent risk factors associated with premature death. While advances continue to improve outcomes of care for people with DFU and amputation, efforts should be directed at primary prevention as well as those for patients in diabetic foot ulcer remission to maximize ulcer-free, hospital-free and activity-rich days.

Up to one-third of the half billion people with diabetes worldwide will develop a diabetic foot ulcer (DFU) over the course of their lifetime. Over half of DFUs will develop an infection. Of these, 17% will require an amputation [1,2,3,4]. Remarkably, people with diabetes fear amputation worse than death [5]. For patients who do not receive amputation and are able to heal their ulcer, 40% will develop a recurrence within 1 year, 65% within 5 years, and greater than 90% within 10 years [1, 6]. The greatest risk factor for a DFU is a previously healed DFU. These silent, sinister complications are now a leading cause of disability worldwide [7, 8]. Despite this high prevalence and morbidity, federal funding for studies related to DFUs remains at a 600-plus-fold disadvantage compared to other diabetes research in terms of public health impact. The disparity is even greater when compared to cancer research [9].

In 2007, we reported a summary of data comparing diabetic foot complications to cancer [10]. We thought that it might be appropriate to refresh this with the best available data as they currently exist. Since that time, more reports have emerged both on cancer mortality [11] and mortality associated with DFU, [12,13,14] Charcot arthropathy, [15,16,17] and diabetes-associated lower extremity amputation [18,19,20,21,22,23,24,25,26,27]. We collected data containing 5-year mortality from studies published after the previous publication in 2007 and calculated a pooled mean.

The mortality rate for people who undergo lower extremity amputation due to a DFU remains alarming: more than half of people with a major amputation will be dead in 5 years [21,22,23,24,25]. (Fig. 1). 5 year mortality for Charcot, DFU, minor and major amputations were 29.0, 30.5, 46.2 and 56.6%, respectively. This is even higher in people with concomitant chronic kidney disease and other comorbidities [25].

Fig. 1

Five Year Mortality of Diabetic Foot Complications and Cancer. Diabetic foot complications compared to cancer. DFU = diabetic foot ulcers [11] = 30.5%. Charcot = Charcot neuroarthropathy of the foot [14]. All Cancer = pooled 5 year survival of all cancers [11]. CLTI = chronic limb threatening ischemia [28, 29]. Major Amputation = above foot amputation [20,21,22, 26, 27]. Minor Amputation = foot level amputation [17, 27]

Certainly, an important component of mortality in people with lower extremity complications of diabetes can be attributed to the severity of comorbidities with these patients often present - namely cardiovascular and renal disease worsened by reduced mobility [7]. This most certainly further reduces the attribution of cause away from lower extremity morbidity and toward a more familiar cardiovascular etiology. Indeed, people with a history of DFU have a life expectancy fully 5 years lower than age and disease-matched controls. The primary cause of death in these patients was listed as ischemic heart disease [30]. It is important to note, however, that, DFU and LEA appear to be more than just a marker of poor health. They are independent risk factors associated with premature death [31].

It is for these reasons that we have argued for a change in the syntax surrounding DFUs and other associated complications. Considering patients with healed DFUs as patients “in remission” rather than formally “healed” makes it easier for the patient, other clinicians, and policymakers to understand the possibility, or as the data suggest, probability, of a recurrence and to better communicate overall risk [1, 32]. It also indicates the need for regular follow-up and helps to prepare the patient for a lifetime of preventative management and mobility training [32]. With this mindset, patients can be properly educated about the dangers of diabetic foot disease and work towards maximizing ulcer-free, hospital-free, and activity-rich days, the same way a cancer survivor works to maximize cancer-free days [33, 34].