Latent autoimmune diabetes of adulthood (LADA): An often misdiagnosed type of diabetes mellitus

Purpose: The purpose of this article is to raise awareness about a frequently misdiagnosed form of diabetes, latent autoimmune diabetes of adulthood (LADA), to describe its clinical and epidemiological characteristics, and to compare them to those of the more common and widely known types of diabetes, type 1 diabetes mellitus (DM) and type 2 DM.
Data sources: A review of the pertinent literature describing the features of LADA from 2000–2007 is summarized.
Conclusions: LADA is a rather common and often underrecognized form of diabetes whose clinical presentation falls somewhere between that of type 1 DM and type 2 DM. From a pathophysiological perspective, it is more closely related to type 1 DM, and some have even used the term type 1.5 diabetes to refer to it; however, it is most often misdiagnosed and treated as type 2 DM.
Implications for practice: Nurse practitioners (NPs) should always consider alternate diagnoses when patients with newly or previously identified adult-onset diabetes mellitus do not fit the traditional stereotype of type 2 DM (i.e., overweight with signs of insulin resistance and a significant family history of diabetes). Statistically, strong consideration must be given to the diagnosis of LADA, especially in those who are of normal weight, show little evidence of insulin resistance, and have hardly any family history of diabetes. Knowing the patient's exact diabetes type can give the NP a much greater understanding of the natural history of the patient's disease, the changes that may occur as the patient ages, and how to optimally manage their diabetes to minimize complications. Likewise, when a patient is correctly diagnosed, they can be empowered to manage their diabetes with the appropriate therapies.     

Metabolic syndrome: time for action

The constellation of dyslipidemia (hypertriglyceridemia and low levels of high-density lipoprotein cholesterol), elevated blood pressure, impaired glucose tolerance, and central obesity is identified now as metabolic syndrome, also called syndrome X. Soon, metabolic syndrome will overtake cigarette smoking as the number one risk factor for heart disease among the U.S. population. The National Cholesterol Education Program-Adult Treatment Panel III has identified metabolic syndrome as an indication for vigorous lifestyle intervention. Effective interventions include diet, exercise, and judicious use of pharmacologic agents to address specific risk factors. Weight loss significantly improves all aspects of metabolic syndrome. Increasing physical activity and decreasing caloric intake by reducing portion sizes will improve metabolic syndrome abnormalities, even in the absence of weight loss. Specific dietary changes that are appropriate for addressing different aspects of the syndrome include reducing saturated fat intake to lower insulin resistance, reducing sodium intake to lower blood pressure, and reducing high-glycemic-index carbohydrate intake to lower triglyceride levels. A diet that includes more fruits, vegetables, whole grains, monounsaturated fats, and low-fat dairy products will benefit most patients with metabolic syndrome. Family physicians can be more effective in helping patients to change their lifestyle behaviors by assessing each patient for the presence of specific risk factors, clearly communicating these risk factors to patients, identifying appropriate interventions to address specific risks, and assisting patients in identifying barriers to behavior change.     

Chronic complications in patients with slowly progressing autoimmune type 1 diabetes (LADA).

OBJECTIVE: To study the prevalence of chronic diabetic complications in patients with the slowly progressing autoimmune form of type 1 diabetes, also referred to as latent autoimmune diabetes in adults (LADA). RESEARCH DESIGN AND METHODS: We evaluated factors associated with chronic diabetic complications in 59 patients with GAD antibodies (GADAs) and age at onset of diabetes >35 years and in 59 GADA-negative type 2 diabetic patients. The prevalence of chronic complications was further compared with the prevalence in 111 type 1 diabetic patients. RESULTS: The LADA patients had lower BMI (P = 0.04), waist-to-hip ratio (P = 0.02 for men and P = 0.03 for women), and fasting C-peptide concentrations (P<0.001) higher HDL2 concentrations (P = 0.04), and less hypertension (58 vs. 75%, P = 0.05) than the type 2 diabetic patients. These differences were even more marked in patients with short disease duration. The prevalence of retinopathy (51 vs. 56%), neuropathy (29 vs. 27%), and microalbuminuria (27 vs. 29%) did not differ between the groups. The type 1 diabetic patients had lower prevalence of neuropathy (13%, P = 0.02) and higher prevalence of retinopathy (76%, P = 0.002) compared with the other groups. Neither the prevalence of coronary heart disease (CHD) (56 vs. 58%) nor cardiovascular mortality (7.4 vs. 12.4%, P = 0.2) significantly differed between the LADA and type 2 diabetic patients. In a multiple logistic regression analysis, glycemic control was associated with CHD (P = 0.02) in the LADA group but not in the type 2 diabetic group. CONCLUSIONS: Glycemic control is a stronger risk factor for cardiovascular disease in LADA patients than in patients with type 2 diabetes. This could be related to the lower prevalence of the metabolic syndrome seen in the former.     

COMMENTARY: Metabolic syndrome and its evolving link to diabetes

Abstract

Background: Although attention deficit/hyperactive disorder (ADHD) is a common comorbidity in individuals who are diagnosed with substance use disorder (SUD), little data currently exist on the utility of screening tools in large samples of adults with SUD in inpatient treatment and the prevalence of ADHD in this population. The aims of this study were to assess the screen positive rate on the Adult ADHD Self Report Scale (ASRS) v.1.1 Screener in a large sample of adults being treated for SUD in a residential treatment facility (RTF) and to establish the imputed prevalence of adult ADHD. Methods: Adults with SUD who were either newly admitted (abstinent for < 1 week) or in treatment in the RTF (abstinent < 3 months) were administered the ASRS v.1.1 Screener. Adults who screened positive on the ASRS v1.1 Screener (≥ 4/6 significant items) were then administered the Adult Clinician Diagnostic Scale (ACDS) v.1.2 to establish a diagnosis of ADHD and the positive predictive value (PPV) in this population. The imputed prevalence of adult ADHD was calculated based on the known rate of ADHD in the screened positive cohort and a calculated rate of ADHD in the screened negative sample based on prior studies of the ASRS v1.1 Screener in community-based and managed care samples. Results: 1064 adults were screened via the ASRS v.1.1 Screener, with 92 screening positive (8.6% had ≥ 4 significant items present). Fifty-three of those who screened positive were diagnosed as having adult ADHD (PPV = 57.6%). The imputed prevalence of adult ADHD in this population was 7.5%. Conclusions: The PPV for the ASRS v1.1 Screener for adult ADHD in this sample of adults with SUD was similar to that observed in a prior study of a managed care sample, but was somewhat less than that observed in the community-based sample. The imputed prevalence rate for comorbid ADHD in this study of adults with SUD in a RTF was similar to, but slightly lower than the prevalence rate of ADHD in patients with any SUD observed in the community-based sample.     

Metabolic syndrome and incident diabetes: current state of the evidence

OBJECTIVE—Our objective was to perform a quantitative review of prospective studies examining the association between the metabolic syndrome and incident diabetes.RESEARCH DESIGN AND METHODS—Using the title terms “diabetes” and “metabolic syndrome” in PubMed, we searched for articles published since 1998.RESULTS—Based on the results from 16 cohorts, we performed a meta-analysis of estimates of relative risk (RR) and incident diabetes. The random-effects summary RRs were 5.17 (95% CI 3.99–6.69) for the 1999 World Health Organization definition (ten cohorts); 4.45 (2.41–8.22) for the 1999 European Group for the Study of Insulin Resistance definition (four cohorts); 3.53 (2.84–4.39) for the 2001 National Cholesterol Education Program definition (thirteen cohorts); 5.12 (3.26–8.05) for the 2005 American Heart Association/National Heart, Lung, and Blood Institute definition (five cohorts); and 4.42 (3.30–5.92) for the 2005 International Diabetes Federation definition (nine cohorts). The fixed-effects summary RR for the 2004 National Heart, Lung, and Blood Institute/American Heart Association definition was 5.16 (4.43–6.00) (six cohorts). Higher number of abnormal components was strongly related to incident diabetes. Compared with participants without an abnormality, estimates of RR for those with four or more abnormal components ranged from 10.88 to 24.4. Limited evidence suggests fasting glucose alone may be as good as metabolic syndrome for diabetes prediction.CONCLUSIONS—The metabolic syndrome, however defined, has a stronger association with incident diabetes than that previously demonstrated for coronary heart disease. Its clinical value for diabetes prediction remains uncertain.Since major organizations such as the World Health Organization (WHO), the European Group for the Study of Insulin Resistance (EGIR), and the National Cholesterol Education Program (NCEP) released definitions of the metabolic syndrome, it has received a great deal of attention in the scientific literature. Much has been learned about the many facets of the syndrome, including its prevalence, incidence, and risks of leading to the development other conditions such as cardiovascular disease and diabetes.Because of the controversy that has enveloped the concept of the metabolic syndrome, a thorough understanding of the association between the syndrome and diabetes—one of the main risks for people with the metabolic syndrome—is critical to furthering the debate about the syndrome''s scientific relevance. At the time of a previous quantitative review, only a limited number of prospective studies of the metabolic syndrome and incident diabetes were available (1). Since that review, additional definitions of the syndrome have joined the previous ones, and the results of more prospective studies have been published. Therefore, the main objective of this study was to provide an updated quantitative review of the estimates of relative risk (RR) from prospective studies of the association between the metabolic syndrome and incident diabetes. In addition, we summarize other pertinent findings of these prospective studies. We also try to place the results into clinical context by comparing metabolic syndrome assessment with other, potentially simpler methods of assessing risk of incident diabetes.     

Metabolic syndrome as a risk factor for diabetes

The metabolic syndrome was initially described as an insulin-resistance syndrome characterized by the clustering of metabolic traits such as high triglycerides, low high-density lipoprotein cholesterol, high blood pressure, abdominal obesity and different degrees of impaired glucose regulation. Although different definitions have been developed by various consensus groups, epidemiological studies demonstrate that they all associate the metabolic syndrome with a similar cardiometabolic risk, which is high for diabetes (ranging between three- and 20-fold), depending on the number of components and the inclusion of impaired fasting glucose, impaired glucose tolerance or both. The latter appear to indicate the failure of the β cell to produce enough insulin to compensate for the increased demand due to insulin resistance. There is a hyperbolic relationship between insulin production and insulin sensitivity, which can be calculated by the disposition index. When this is altered there is a higher risk of developing Type 2 diabetes. There have been no clinical trials in subjects selected by the diagnosis of metabolic syndrome, but structured lifestyle changes have been tested in people with impaired fasting glucose/impaired glucose tolerance and have been able to reduce incident Type 2 diabetes by almost 50%, as long as a weight loss of at least 5% is achieved. Oral antidiabetic and anti-obesity drugs have also been successful to a lesser degree. Some fibrates have reduced or delayed incident diabetes. Extended-release niacin has a neutral effect and statins are controversial. ACE inhibitors and ARBs are the antihypertensive agents least associated with incident diabetes.     

Similar genetic features and different islet cell autoantibody pattern of latent autoimmune diabetes in adults (LADA) compared with adult-onset type 1 diabetes with rapid progression

OBJECTIVE: To compare the clinical parameters, C-peptide levels, pattern of islet cell-specific autoantibodies, and prevalence of predisposing genotypes in subjects with latent autoimmune diabetes in adults (LADA) and those with adult-onset type 1 diabetes with rapid progression. RESEARCH DESIGN AND METHODS: We evaluated the clinical parameters, C-peptide levels, and islet cell-specific autoantibodies in 54 LADA, 57 adult-onset type 1 diabetic, and 190 type 2 diabetic patients. Islet cell autoantibodies were also compared between subgroups of newly diagnosed patients with LADA and those with newly diagnosed adult-onset and childhood-onset type 1 diabetes. The genetic study was performed in subjects with LADA and those with adult-onset type 1 diabetes in comparison with a control population. RESULTS: There were no differences in the clinical parameters between LADA and adult-onset type 1 diabetes. Patients with LADA had lower BMI (P < 0.0001), waist-to-hip ratio (0.0029), total cholesterol (P = 0.001), and triglycerides (P = 0.001); higher HDL cholesterol levels (P < 0.0001); and lower prevalence of hypertension (P = 0.0028) compared with patients with type 2 diabetes. C-peptide levels were similar at onset (P = 0.403) but decreased less rapidly in LADA than in adult-onset type 1 diabetes (P = 0.0253). Single-autoantibody positivity was more often seen in LADA than in type 1 diabetes (P = 0.0001). The prevalence of predisposing HLA-DQB1*0302, -DR4, -DR3, and -DR3/DR4 genotypes and the DR4-DQB1*0302 haplotype were increased in both LADA and adult-onset type 1 diabetic subjects compared with the control population. There were no differences in the frequencies of these risk alleles and haplotypes between the two patient groups. CONCLUSIONS: Subjects with LADA had clinical characteristics similar to those with adult-onset type 1 diabetes with rapid progression. C-peptide levels did not differ at onset but decreased less rapidly in LADA. Patients with LADA rather had single islet cell-specific autoantibody positivity. The prevalence of HLA-DQB1*0302, -DR4, -DR3, and -DR3/DR4 risk alleles and the DR4-DQB1*0302 high-risk haplotype did not differ in the two forms of autoimmune diabetes.     

Metabolic syndrome and other factors associated with increased risk of diabetes

The prevalence of diabetes has increased dramatically in the last 3 decades. Metabolic syndrome is a strong risk factor for incident diabetes. Among components of metabolic syndrome, obesity and abnormal carbohydrate metabolism are the most significant predictors. Primary care physicians should identify patients at risk and monitor their fasting glucose and/or postprandial glucose to enable timely diagnosis of diabetes and appropriate interventions. Lifestyle interventions that help reduce body weight and pharmacologic interventions that address insulin resistance and/or postprandial glycemia may help prevent diabetes. Intensive cardiovascular risk factor management should be an integral component of any diabetes prevention plan.     

Metabolic syndrome: definition and therapeutic implications

The collection of impaired glucose metabolism, central obesity, elevated blood pressure, and dyslipidemia is identified as metabolic syndrome (MetS). It is estimated that approximately 25% of the world's population has MetS. In the United States, MetS is more common in men and Hispanics, and its incidence increases with age. Metabolic syndrome increases the risk of developing cardiovascular disease and type 2 diabetes mellitus. The underlying risk factors include insulin resistance and abdominal obesity. Confusion about MetS exists in part due to the lack of a consensus definition and treatment protocol. Treatment of MetS begins with therapeutic lifestyle changes and then pharmacologic treatment of the syndrome's individual components. Effective interventions include diet modification, exercise, and use of pharmacologic agents to treat risk factors. Weight loss and increasing physical activity significantly improve all aspects of MetS. A diet that includes more fruits, vegetables, whole grains, monounsaturated fats, and low-fat dairy products will benefit most patients with MetS. Physicians can be most effective in advising patients by customizing specific lifestyle recommendations after assessing patients for the presence of risk factors.