Beverly Orsak

Effect of adipose tissue insulin resistance on metabolic parameters and liver histology in obese patients with nonalcoholic fatty liver disease

The role of adipose tissue insulin resistance in the pathogenesis of nonalcoholic fatty liver disease (NAFLD) remains unclear. To evaluate this, we measured in 207 patients with NAFLD (age = 51 ± 1, body mass index = 34.1 ± 0.3 kg/m2) and 22 controls without NAFLD (no NAFLD) adipose tissue insulin resistance by means of a validated index (Adipo‐IRi = plasma free fatty acids [FFA] x insulin [FPI] concentration) and as the suppression of plasma FFA during an oral glucose tolerance test and by a low‐dose insulin infusion. We also explored the relationship between adipose tissue insulin resistance with metabolic and histological parameters by dividing them based on quartiles of adipose tissue insulin resistance (Adipo‐IRi quartiles: Q1 = more sensitive; Q4 = more insulin resistant). Hepatic insulin resistance, measured as an index derived from endogenous glucose production x FPI (HIRi), and muscle insulin sensitivity, were assessed during a euglycemic insulin clamp with 3‐[3H] glucose. Liver fat was measured by magnetic resonance imaging and spectroscopy, and a liver biopsy was performed to assess liver histology. Compared to patients without steatosis, patients with NAFLD were insulin resistant at the level of adipose tissue, liver, and skeletal muscle and had higher plasma aspartate aminotransferase and alanine aminotransferase, triglycerides, and lower high‐density lipoprotein cholesterol and adiponectin levels (all P < 0.01). Metabolic parameters, hepatic insulin resistance, and liver fibrosis (but not necroinflammation) deteriorated as quartiles of adipose tissue insulin resistance worsened (all P < 0.01). Conclusion: Adipose tissue insulin resistance plays a key role in the development of metabolic and histological abnormalities of obese patients with NAFLD. Treatment strategies targeting adipose tissue insulin resistance (e.g., weight loss and thiazolidinediones) may be of value in this population. (HEPATOLOGY 2012)

Long-Term Pioglitazone Treatment for Patients With Nonalcoholic Steatohepatitis and Prediabetes or Type 2 Diabetes Mellitus: A Randomized Trial

Nonalcoholic fatty liver disease (NAFLD) is reaching epidemic proportions worldwide (1) and is the most common chronic liver condition in obese patients with prediabetes or type 2 diabetes mellitus (T2DM). Histologic findings range from isolated steatosis (with no or minimal inflammation) to severe nonalcoholic steatohepatitis (NASH) and variable perisinusoidal or perivenular fibrosis (2). Patients with T2DM and NASH have the highest risk for cirrhosis and hepatocellular carcinoma (3, 4), and the presence of NAFLD seems to worsen microvascular and macrovascular complications of diabetes (57). Given that most patients with T2DM have NAFLD (812) and many are at risk for NASH even if they have normal liver aminotransferase levels (6, 9, 13, 14), it is surprising that few trials have focused on this population. This distinction (patients with NASH with vs. without T2DM) is relevant because additional metabolic factors, such as hyperglycemia (15, 16), lower adiponectin levels (17, 18), worse dyslipidemia (19, 20), and more severe insulin resistance and hepatic steatosis (10, 16, 1821), may account for the higher rates of severe liver disease observed in patients with T2DM (22). Although the cause of NASH is multifactorial and treatment remains challenging (23), a major factor is the increase in liver triglyceride content caused by chronic release of free fatty acids (FFAs) from insulin-resistant dysfunctional adipose tissue (7, 2427). Because thiazolidinediones target insulin resistance and adipose tissue dysfunction or inflammation that promotes hepatic lipotoxicity in NASH (7, 22, 28) (which is also a prominent feature of T2DM [15]), they may be more helpful for treating steatohepatitis in this population. In predominantly nondiabetic patients with NASH, several studies have reported variable degrees of histologic benefit with thiazolidinediones (2933). In the largest study to date in patients without T2DM (34), pioglitazone was no better than placebo for the primary outcome but was beneficial for secondary outcomes, such as resolution of NASH. However, in patients with prediabetes or T2DM, the only available randomized, controlled trial is a relatively small proof-of-concept study (35). This is disappointing given that there are 29.1 million adults with diabetes (>90% with T2DM) and 86 million with prediabetes (36) in the United States, many of whom are at risk for cirrhosis from NASH. Moreover, because pioglitazone may also halt the progression of prediabetes to T2DM (37), defining its role in patients with prediabetes and NASH is critical. Finally, safety concerns about the long-term use of thiazolidinediones remain (38, 39); therefore, studies with extended thiazolidinedione exposure are needed before a pioglitazone-based approach can be embraced in this population. The aim of our study was to assess the efficacy and safety of long-term pioglitazone treatment in improving liver histologic outcomes in patients with NASH and prediabetes or T2DM. Methods Design Overview This was a single-center, parallel-group, randomized (1:1 allocation), placebo-controlled study, conducted between December 2008 (first patient enrolled) and December 2014 (final data collection). Participants, investigators, and health care providers were blinded to treatment assignment throughout the study. The Institutional Review Board at the University of Texas Health Science Center at San Antonio (UTHSCSA) approved the study, and all participants provided written informed consent before enrollment. In October 2009, while updating registry data for another study, investigators discovered that this trial, which they thought had been registered by other study personnel, was not registered. At the time of registration (ClinicalTrials.gov: NCT00994682), 29 patients (of 97 anticipated) were enrolled in the study. None of these patients had had the follow-up metabolic measurements or liver biopsies (primary outcome) that were to be performed at 18 months, and no interim analyses were done before the trial was registered. A recent review of ClinicalTrials.gov (November 2015) revealed that the initial trial registration data erroneously stated that patients with normal glucose tolerance would be randomly assigned to treatment or placebo. Given that the trials eligibility criteria required patients to have an abnormal oral glucose tolerance test (OGTT) result (that is, prediabetes or T2DM), the investigators never planned to enroll patients with normal glucose tolerance. This error in trial registration was corrected by the principal investigator. The trial registry states that the primary end point is liver histologic outcomes (Kleiner criteria [40]) at 18 months, and these data are presented in Appendix Table 1. In this article, the primary end point is defined as a reduction of at least 2 points in 2 categories of the NAFLD activity score (NAS) without worsening of fibrosis, an outcome that was not specified in the original registration. This end point has been accepted by investigators in this field as representing significant change in liver histologic outcomes in clinical trials involving patients with NASH (34, 4143). Some secondary outcomes that were assessed, such as insulin secretion, prevention of the onset of T2DM or reversal of glucose intolerance, measurement of visceral fat by magnetic resonance imaging, bone density measurement via dual-energy x-ray absorptiometry (DXA), plasma measurements of bone metabolism, and molecular metabolic pathways, are not reported in this article. Appendix Table 1. Liver Histologic Variables at Baseline and After 18 mo, Based on Observed Data* Setting and Participants Participants were recruited from the general population of San Antonio, Texas, via newspaper advertisements and from the endocrinology and hepatology clinics at UTHSCSA and the Veterans Affairs Medical Center. Persons were eligible for the trial if they had histologically confirmed NASH and either prediabetes or T2DM. All patients had a screening 2-hour OGTT to diagnose or confirm a diagnosis of prediabetes or T2DM. Prediabetes was defined as impaired fasting glucose (5.6 to 6.9 mmol/L [100 to 125 mg/dL]), impaired glucose tolerance (7.8 to 11.1 mmol/L [140 to 199 mg/dL] on an OGTT), or a hemoglobin A1c level of 5.7% to 6.4%. Exclusion criteria included use of thiazolidinediones or vitamin E; other causes of liver disease (22) or abnormal laboratory results (such as an aspartate aminotransferase [AST] or alanine aminotransferase [ALT] level 3 times the upper limit of normal [ULN]); type 1 diabetes mellitus; or severe heart, hepatic, or renal disease. Detailed inclusion and exclusion criteria are provided in the Appendix. Randomization and Interventions After initial screening (medical history, physical examination, laboratory tests, and 75-g OGTT), patients began receiving placebo and were instructed by the research dietician (C.D.) to keep physical activity and diet constant during the run-in phase (mean duration, 1 month). After completion of baseline metabolic measurements, participants were prescribed a hypocaloric diet (500kcal/d deficit from the calculated weight-maintaining diet) and were randomly assigned in a 1:1 ratio to either pioglitazone (Actos [Takeda Pharmaceuticals]), 30 mg/d (titrated after 2 months to 45 mg/d), or placebo. Randomization (computer-generated) and patient allocation were performed by the research pharmacist without stratification and using a block factor of 4, which was unknown to investigators. Takeda Pharmaceuticals provided pioglitazone and placebo pills with identical physical characteristics, which were stored at the research pharmacy and dispensed in identical bottles. Outcomes and Follow-up The primary outcome was a reduction of at least 2 points in 2 histologic categories of the NAS without worsening of fibrosis after 18 months of therapy. Secondary liver histologic outcomes included resolution of NASH; improvement in individual histologic scores; or improvement in a combined histologic outcome, defined as a reduction in ballooning with at least a 2-point improvement in the NAS or an absolute NAS of 3 or lower (with improvement in steatosis or inflammation) without worsening of fibrosis. Baseline liver biopsy specimens were read by a team of experienced clinical pathologists to establish or rule out the presence of NASH and thus determine whether patients were included or excluded. At the end of the study, all biopsy specimens were reread by an experienced research pathologist (F.T.), who was blinded to patient identity, intervention assignment, and pretreatment or posttreatment sequence (0, 18, or 36 months). Biopsy specimens were read by the research pathologist 2 times, with good to excellent intraobserver variability (agreement >75% for all histologic parameters). Diagnosis of definite NASH was defined as zone 3 accentuation of macrovesicular steatosis (any grade), hepatocellular ballooning (any degree), and lobular inflammatory infiltrates (any amount). The NAS was calculated as the sum of the steatosis, inflammation, and ballooning grades from the liver biopsy, and histopathologic changes were determined by using standard criteria (44). Additional secondary outcomes included the following: 1) fasting plasma glucose, fasting plasma insulin, FFA, hemoglobin A1c, fasting plasma lipid profile, adiponectin, and cytokeratin-18 concentrations; 2) total body fat percentage, measured by DXA; 3) hepatic triglyceride content, measured by magnetic resonance and proton spectroscopy (1H-MRS) as previously described (14, 16, 35, 45) (baseline and 18 months only); 4) glucose tolerance and insulin secretion on an OGTT; 5) endogenous glucose production (EGP), rate of glucose disappearance (R d), and insulin-induced suppression of EGP and plasma FFA concentration, all measured during a euglycemic insulin clamp with tritiated glucose and indirect calorimetry (baseline and 18 months only) as previously reported (16

Prevalence of Prediabetes and Diabetes and Metabolic Profile of Patients With Nonalcoholic Fatty Liver Disease (NAFLD)

OBJECTIVE Prediabetes and type 2 diabetes mellitus (T2DM) are believed to be common and associated with a worse metabolic profile in patients with nonalcoholic fatty liver disease (NAFLD). However, no previous study has systematically screened this population. RESEARCH DESIGN AND METHODS We studied the prevalence and the metabolic impact of prediabetes and T2DM in 118 patients with NAFLD. The control group comprised 20 subjects without NAFLD matched for age, sex, and adiposity. We measured 1) plasma glucose, insulin, and free fatty acid (FFA) concentration during an oral glucose tolerance test; 2) liver fat by magnetic resonance spectroscopy (MRS); 3) liver and muscle insulin sensitivity (euglycemic insulin clamp with 3-[3H]glucose); and 4) indexes of insulin resistance (IR) at the level of the liver (HIRi= endogenous glucose production × fasting plasma insulin [FPI]) and adipose tissue (Adipo-IRi= fasting FFA × FPI). RESULTS Prediabetes and T2DM was present in 85% versus 30% in controls (P < 0.0001), all unaware of having abnormal glucose metabolism. NAFLD patients were IR at the level of the adipose tissue, liver, and muscle (all P < 0.01–0.001). Muscle and liver insulin sensitivity were impaired in patients with NAFLD to a similar degree, whether they had prediabetes or T2DM. Only adipose tissue IR worsened in T2DM and correlated with the severity of muscle (r = 0.34; P < 0.001) and hepatic (r = 0.57; P < 0.0001) IR and steatosis by MRS (r = 0.35; P < 0.0001). CONCLUSIONS Patients with NAFLD may benefit from early screening for T2DM, because the prevalence of abnormal glucose metabolism is much higher than previously appreciated. Regardless of glucose tolerance status, severe IR is common. In patients with T2DM, adipose tissue IR appears to play a major role in the severity of NAFLD.

High Prevalence of Nonalcoholic Fatty Liver Disease in Patients With Type 2 Diabetes Mellitus and Normal Plasma Aminotransferase Levels.

CONTEXT AND OBJECTIVE Nonalcoholic fatty liver disease (NAFLD) and its more severe form with steatohepatitis (NASH) are common in patients with type 2 diabetes mellitus (T2DM). However, they are usually believed to largely affect those with elevated aminotransferases. The aim of this study was to determine the prevalence of NAFLD by the gold standard, liver magnetic resonance spectroscopy ((1)H-MRS) in patients with T2DM and normal aminotransferases, and to characterize their metabolic profile. PARTICIPANTS AND METHODS We recruited 103 patients with T2DM and normal plasma aminotransferases (age, 60 ± 8 y; body mass index [BMI], 33 ± 5 kg/m(2); glycated hemoglobin [A1c], 7.6 ± 1.3%). We measured the following: 1) liver triglyceride content by (1)H-MRS; 2) systemic insulin sensitivity (homeostasis model assessment-insulin resistance); and 3) adipose tissue insulin resistance, both fasting (as the adipose tissue insulin resistance index: fasting plasma free fatty acids [FFA] × insulin) and during an oral glucose tolerance test (as the suppression of FFA). RESULTS The prevalence of NAFLD and NASH were much higher than expected (50% and 56% of NAFLD patients, respectively). The prevalence of NAFLD was higher in obese compared with nonobese patients as well as with increasing BMI (P = .001 for trend). Higher plasma A1c was associated with a greater prevalence of NAFLD and worse liver triglyceride accumulation (P = .01). Compared with nonobese patients without NAFLD, patients with NAFLD had severe systemic (liver/muscle) and, particularly, adipose tissue (fasting/postprandial) insulin resistance (all P < .01). CONCLUSIONS The prevalence of NAFLD is much higher than previously believed in overweight/obese patients with T2DM and normal aminotransferases. Moreover, many are at increased risk of NASH. Physicians should have a lower threshold for screening patients with T2DM for NAFLD/NASH.

The role of liver fat and insulin resistance as determinants of plasma aminotransferase elevation in nonalcoholic fatty liver disease

Plasma aminotransferases (aspartate aminotransferase [AST] and alanine aminotransferase [ALT]) are usually increased in patients with nonalcoholic fatty liver disease (NAFLD). However, the factors behind their elevation remain unclear. The aim of this study was to assess the role of insulin resistance (IR) and liver triglyceride content in relation to histology in patients with NAFLD/nonalcoholic steatohepatitis (NASH) with normal or elevated ALT levels. To this end, we enrolled 440 patients, divided into three groups: no NAFLD (n = 60); NAFLD with normal ALT (n = 165); and NAFLD with elevated ALT (n = 215). We measured: (1) liver fat by proton magnetic resonance spectroscopy (1H‐MRS); (2) severity of liver disease by biopsy (n = 293); and (3) insulin sensitivity in liver, muscle, and adipose tissue by a euglycemic hyperinsulinemic clamp with 3‐3H‐glucose. Patients with NAFLD and elevated ALT, even when well matched for body mass index to those with normal ALT, had worse adipose tissue insulin resistance (ATIR; P < 0.0001), higher liver triglyceride content (P < 0.0001), and lower plasma adiponectin (P < 0.05), but no differences in hepatic insulin resistance. Similar results were found when only patients with NASH were compared: both ATIR (P < 0.0001) and liver triglyceride content by 1H‐MRS (P < 0.0001) were worse in NASH with elevated ALT. Consistent with the 1H‐MRS data, steatosis on liver biopsy was also significantly increased in patients with NASH and elevated ALT levels (P < 0.0001). However, and most important, there were no differences in inflammation (P = 0.62), ballooning (P = 0.13), or fibrosis (P = 0.12). Conclusion: In patients with NAFLD or NASH, ATIR (but not HIR) and liver triglyceride content are major factors in the elevation of plasma aminotransferase levels. Patients with normal versus elevated ALT had similar severity of NASH, suggesting that plasma aminotransferase levels are misleading parameters for guiding clinical management. (Hepatology 2015;61:153–160)

Role of ethnicity in overweight and obese patients with nonalcoholic steatohepatitis

The role of ethnicity in determining disease severity in nonalcoholic steatohepatitis (NASH) remains unclear. We recruited 152 patients with biopsy‐proven NASH, 63% of whom were Hispanic and 37% of whom were Caucasian. Both groups were well matched for age, sex, and total body fat. We measured: (1) liver fat by magnetic resonance imaging and spectroscopy; (2) fasting plasma glucose, fasting plasma insulin (FPI), and free fatty acid (FFA) levels; (3) total body fat by dual energy x‐ray absorptiometry (DXA); (4) liver and muscle insulin sensitivity (insulin clamp with 3‐[3H] glucose); (5) insulin resistance at the level of the liver (fasting endogenous glucose production derived from 3‐[3H] glucose infusion × FPI) and adipose tissue (fasting FFA × FPI). Liver fat was slightly, but not significantly, higher in Hispanic vs. Caucasian patients (27 ± 2% vs. 24 ± 2%, p = 0.16). However, this trend did not translate into worse liver steatosis, necroinflammation or fibrosis. Patients with NASH had severe hepatic, adipose tissue and muscle insulin resistance versus healthy subjects without NASH nonalcoholic fatty liver disease, but there were no differences between both ethnic groups on these parameters. However, Hispanics versus Caucasians with type 2 diabetes mellitus (T2DM) had a trend for worse hepatic/adipose tissue insulin resistance and fibrosis. Conclusion: When Hispanic and Caucasian patients with NASH are well matched for clinical parameters, particularly for adiposity, slightly higher liver fat content is not associated with worse hepatic insulin resistance or more severe NASH on histology. Hispanic ethnicity does not appear to be a major determinant of disease severity in NASH, although those with diabetes may be at greater risk of fibrosis. Given the higher risk of T2DM in Hispanics, long‐term studies are needed to define their risk of disease progression. (HEPATOLOGY 2011;)

Clinical value of liver ultrasound for the diagnosis of nonalcoholic fatty liver disease in overweight and obese patients.

Liver ultrasound (US) is usually used in the clinical setting for the diagnosis and follow‐up of patients with nonalcoholic fatty liver disease (NAFLD). However, no large study has carefully assessed its performance using a semiquantitative ultrasonographic scoring system in overweight/obese patients, in comparison to magnetic resonance spectroscopy (1H‐MRS) and histology.

Metabolic Impact of Nonalcoholic Steatohepatitis in Obese Patients With Type 2 Diabetes

OBJECTIVE Nonalcoholic steatohepatitis (NASH) is increasingly common in obese patients. However, its metabolic consequences in patients with type 2 diabetes mellitus (T2DM) are unknown. RESEARCH DESIGN AND METHODS We studied 154 obese patients divided in four groups: 1) control (no T2DM or NAFLD), 2) T2DM without NAFLD, 3) T2DM with isolated steatosis, and 4) T2DM with NASH. We evaluated intrahepatic triglycerides by proton MRS (1H-MRS) and assessed insulin secretion/resistance during an oral glucose tolerance test and a euglycemic-hyperinsulinemic clamp with glucose turnover measurements. RESULTS No significant differences among groups were observed in sex, BMI, or total body fat. Metabolic parameters worsened progressively with the presence of T2DM and the development of hepatic steatosis, with worse hyperinsulinemia, insulin resistance, and dyslipidemia (hypertriglyceridemia and low HDL cholesterol) in those with NASH (P < 0.001). Compared with isolated steatosis, NASH was associated with more dysfunctional and insulin-resistant adipose tissue (either as insulin suppression of plasma FFA [33 ± 3 vs. 48 ± 6%] or adipose tissue insulin resistance index [9.8 ± 1.0 vs. 5.9 ± 0.8 mmol/L ⋅ µIU/mL]; both P < 0.03). Furthermore, insulin suppression of plasma FFA correlated well with hepatic steatosis (r = –0.62; P < 0.001) and severity of steatohepatitis (rs = −0.52; P < 0.001). Hepatic insulin sensitivity was also more significantly impaired among patients with T2DM and NASH, both fasting and with increasing insulin levels within the physiological range (10 to 140 µIU/mL), compared with other groups. CONCLUSIONS In obese patients with T2DM, the presence of NAFLD is associated with more severe hyperinsulinemia, dyslipidemia, and adipose tissue/hepatic insulin resistance compared with patients without NAFLD. The unfavorable metabolic profile linked to NAFLD should prompt strategies to identify and treat this population early on.

Liver Safety of Statins in Prediabetes or T2DM and Nonalcoholic Steatohepatitis: Post-hoc Analysis of a Randomized Trial.

Context Patients with nonalcoholic fatty liver disease have a high cardiovascular risk, but statins are rarely prescribed because of fear of hepatotoxicity. Objective To prospectively assess the long-term safety of statins in patients with prediabetes/type 2 diabetes mellitus (T2DM) and nonalcoholic steatohepatitis (NASH). Design Post hoc analysis of statin use during a randomized, controlled trial assessing pioglitazone vs placebo for NASH. Patients A total of 101 patients (86 receiving statins) with biopsy-proven NASH and prediabetes/T2DM were followed for up to 36 months. Interventions Oral glucose tolerance test and percutaneous liver biopsy (baseline, month 18, and month 36); liver magnetic resonance spectroscopy and euglycemic insulin clamp (baseline and month 18). Main Outcome Measures Histologic and biochemical safety of statin use among patients with NASH. Results Only 37% of patients were receiving statins at enrollment despite their high cardiovascular risk. Statin nonusers had higher plasma alanine aminotransferase levels but similar histologic severity of liver disease at baseline. In both statin users and nonusers, the same number of patients (n = 4) had a twofold or greater increase in plasma aminotransferases during follow-up. One statin nonuser was discontinued from the study because of this elevation. Values returned to normal without any active measure in all other cases. No changes on liver histology or hepatic insulin resistance were observed in patients with NASH newly started on a statin and receiving placebo during the main study. Conclusions Statin therapy is safe in patients with prediabetes/T2DM and NASH. Given their high cardiovascular risk, statin therapy should be encouraged in this population.

Response to Pioglitazone in Patients With Nonalcoholic Steatohepatitis With vs Without Type 2 Diabetes

Background & Aims Pioglitazone is effective for long‐term treatment of patients with nonalcoholic steatohepatitis (NASH) with prediabetes or type 2 diabetes. However, it is not clear how the presence of type 2 diabetes affects the drug’s efficacy. We compared metabolic and histologic responses to pioglitazone in patients with NASH and prediabetes vs type 2 diabetes. Methods We performed a prospective study of adults with biopsy‐proven NASH (52 with type 2 diabetes and 49 with prediabetes), enrolled from the general population of San Antonio, Texas, from 2008 through 2014. After a run‐in period of approximately 4 weeks, when all baseline measurements were made (liver magnetic resonance proton spectroscopy, euglycemic insulin clamp with glucose turnover measurements, dual‐energy absorptiometry, and liver biopsy), subjects were randomly assigned to groups given pioglitazone or placebo (45 mg/d) for 18 months; all procedures performed at baseline were then repeated. The primary outcome was a reduction in nonalcoholic fatty liver disease activity score of 2 points or more (for at least 2 components) without worsening of fibrosis (and expressed as difference vs placebo). Secondary outcomes included NASH resolution, individual histologic components, intrahepatic triglyceride content (measured by 1H magnetic resonance spectroscopy), and insulin sensitivity (measured by euglycemic insulin clamp). Results The primary outcome was met by 48% of patients with type 2 diabetes vs 46% without diabetes. Resolution of NASH was achieved in 44% of patients with type 2 diabetes vs 26% without diabetes. A significant reduction in fibrosis, from baseline, was observed only in patients with type 2 diabetes (P = .035). Intrahepatic triglyceride content was reduced by 11% ± 2% in patients with diabetes vs a reduction of 9% ± 2% in patients without diabetes (P = .62); the plasma level of alanine aminotransferase was reduced by 50 ± 10 U/L in patients with diabetes vs a reduction of 36 ± 5 U/L in patients without diabetes (P = .22). Pioglitazone was associated with a significantly greater insulin sensitivity in adipose tissue of patients with diabetes vs without diabetes (P < .001), but nonsignificant differences in responses in hepatic (P = .49) and skeletal muscle (P = .32) insulin sensitivity. Conclusions In a prospective study, we found pioglitazone to be effective in patients with and without type 2 diabetes. However, pioglitazone reduced liver fibrosis and increased adipose tissue insulin sensitivity at significantly greater levels in patients with type 2 diabetes than in patients with prediabetes. Further studies are needed to determine the mechanisms by which pioglitazone reduces liver disease in patients with type 2 diabetes. ClinicalTrials.gov: NCT00994682.