DOI: 10.2337/diacare.29.01.06.dc05-1058 © 2006 by the American Diabetes Association
Impact of Active Versus Usual Algorithmic Titration of Basal Insulin and Point-of-Care Versus Laboratory Measurement of HbA1c on Glycemic Control in Patients With Type 2 DiabetesThe Glycemic Optimization with Algorithms and Labs at Point of Care (GOAL A1C) trial
1 Division of Endocrinology, Department of Medicine, University of Florida, Gainesville, Florida Address correspondence and reprint requests to Laurence Kennedy, MD, Professor and Chief, Division of Endocrinology, Department of Medicine, Shands Hospital at the University of Florida, Gainesville, FL 32610. E-mail: kenneal{at}medicine.ufl.edu
OBJECTIVEThe objective of this study was to assess the impact of active versus usual monitoring of algorithmic insulin titration and point-of-care (POC) versus laboratory HbA1c (A1C) measurement on glycemic control in primary care. RESEARCH DESIGN AND METHODSThe Glycemic Optimization with Algorithms and Labs at Point of Care (GOAL A1C) study was a 24-week, randomized, parallel-group, four-arm, open-label study of 7,893 adults with type 2 diabetes uncontrolled by oral antidiabetic agents and requiring insulin. Patients were randomly assigned by investigators from 2,164 sites in the U.S. to insulin glargine with either 1) usual (no unsolicited contact between visits) insulin titration using a simple algorithm with laboratory A1C testing, 2) usual titration with POC A1C testing, 3) active (weekly monitored) titration with laboratory A1C testing, or 4) active titration with POC A1C testing. Outcome measures included a change in A1C and fasting self-monitoring of blood glucose (SMBG) levels, percentage of patients achieving A1C <7.0%, and hypoglycemia frequency. RESULTSSignificant A1C and SMBG reductions were observed in all arms (P < 0.0001). Compared with usual insulin titration, active titration achieved greater A1C reduction (1.5 vs. 1.3%; P < 0.0001), SMBG reduction (88 vs. 79 mg/dl; P < 0.0001), and proportion of patients achieving A1C <7.0% (38 vs. 30%; P < 0.0001). Among patients receiving active titration, POC A1C testing was associated with an increase in the proportion achieving an A1C <7.0% (41% for POC vs. 36% for laboratory; P < 0.0001). Hypoglycemia rates were low (usual vs. active groups: 3.7 vs. 6.0 all confirmed episodes/patient-year [P < 0.001]; 0.09 vs. 0.14 severe episodes/patient-year [NS]). CONCLUSIONSIn a predominantly primary care setting, addition of insulin glargine using a simple algorithm achieved significant improvements in glycemic control in patients with type 2 diabetes in all four study arms. Active titration resulted in significant incremental improvements in glycemic control, and, among patients receiving active titration, POC A1C testing resulted in a greater portion achieving A1C <7.0%.
Abbreviations: GOAL A1C, Glycemic Optimization with Algorithms and Labs at Point of Care ITT, intent to treat LOCF, last observation carried forward POC, point of care SMBG, self-monitoring of blood glucose TEAE, treatment-emergent adverse event TZD, thiazolidinedione
Combination therapy with basal insulin and oral antidiabetic agents can safely improve glycemic control (13); however, insulin is often delayed or inadequately titrated in patients with type 2 diabetes, resulting in failure to achieve glycemic targets (4,5). Recently, a forced-titration algorithm for basal insulin was shown to be effective in reducing HbA1c (A1C) in two large multicenter clinical trials (2,6). Both trials used the same titration algorithm, but only in the trial in which algorithm adherence was actively monitored was an average A1C level of <7.0% achieved in the majority of patients. We seek here to formally test the impact of active versus usual monitoring of algorithm adherence. Another monitoring approach that may improve glycemic control is point-of-care (POC) A1C testing. The immediate availability of an A1C result during an office visit may enhance the ability to make timely and appropriate adjustments to therapy and facilitate patient education (7,8). The anticipated benefits of POC A1C testing compared with routine A1C testing have yet to be demonstrated convincingly (9). The Glycemic Optimization with Algorithms and Labs at Point of Care (GOAL A1C) study was designed to examine the influence of active (weekly monitored) insulin titration versus usual titration of insulin glargine using a simple titration algorithm and office-based POC A1C testing versus laboratory A1C testing on glycemic control in patients with type 2 diabetes uncontrolled by oral antidiabetic therapy. Secondary objectives were to evaluate whether such treatment strategies to facilitate achievement of glycemic goals could be readily implemented in a predominantly primary care setting and to assess demographic and epidemiologic characteristics in a large nationwide sample of patients with type 2 diabetes.
Eligible patients included men and women 18 years of age or older who had a diagnosis of type 2 diabetes for at least 1 year, had inadequate glycemic control (A1C >7.0%) despite diet, exercise, and oral antidiabetic agents, and were identified by their physicians as candidates for starting insulin. Patients had to be taking stable doses of their current oral antidiabetic medications for at least 2 months before randomization.
Exclusion criteria included severe heart failure (cardiac status New York Heart Association Classification IIIIV), known clinically significant renal or hepatic disease (serum creatinine This was a 24-week, randomized, parallel-group, four-arm, open-label study conducted between 26 March 2002 and 30 September 2003 at 2,164 sites in the U.S. The protocol was reviewed and approved by local ethical review committees/institutional review boards. Each study site was to randomly assign four patients (i.e., one patient to each study arm). Eligible patients gave informed consent and were consecutively and immediately randomly assigned (no screening period) through a telephone interactive voice response system to begin algorithmic titration of insulin glargine in one of the following arms: 1) usual titration of insulin glargine and laboratory A1C testing, 2) usual titration and POC A1C testing, 3) active titration and laboratory A1C testing, or 4) active titration and POC A1C testing. "Usual titration" was defined as patient instruction at study visits (every 6 weeks) but no unsolicited patient contact between visits. Active titration was defined as weekly patient contact (via telephone, E-mail, or fax) to evaluate general well-being, review glucose values, and reinforce the insulin titration and follow-up visit schedule, in addition to instruction at study visits occurring every 6 weeks. Self-monitoring of blood glucose (SMBG) levels, insulin dose changes, and hypoglycemic events were documented on titration sheets and faxed weekly by study coordinators at each site to the centralized study monitor. At each visit, patients in the POC A1C arms had A1C values tested via fingerstick using the A1cNow monitor (Metrika, Sunnyvale, CA). Patients in the central laboratory A1C testing arms (Quest Diagnostics Clinical Trials Laboratory, Van Nuys, CA) did not have current A1C values available at study visits. The laboratory A1C value was measured at each visit and then made available to the physician within 2 or 3 days; among patients assigned to usual titration with laboratory A1C testing, this value may not have been acted upon until the subsequent study visit (because there was no unsolicited patient contact).
Protocol and study medications
Patients were to continue their oral antidiabetic agents at a fixed dose (dose at randomization). Thiazolidinediones (TZDs) were discontinued at or before randomization because of concerns about their use with insulin (11,12). Thus, with the exception of TZDs and, in some cases, metformin, patients continued their oral antidiabetic agents and received long-acting (24-h) basal insulin glargine (Lantus; Aventis Pharmaceuticals) once daily, subcutaneously, at bedtime. Patients were instructed on insulin administration and provided with a one-page instructional pamphlet on the dose titration (APPENDIX 1). The starting dose of insulin glargine was 10 IU/day, titrated weekly until the average of the last 24 days of morning fasting SMBG values was
Outcome assessments
Standardization procedures
Statistical methods The primary outcome (change from baseline in A1C) was analyzed using ANCOVA with baseline A1C as the primary covariate. The secondary outcome (change in SMBG from baseline) was analyzed in the same manner with baseline SMBG as the primary covariate. APPENDIX 3 provides additional details on the statistical analyses.
The number and percentage of patients achieving the goal A1C <7.0% were summarized descriptively. A logistic regression model (treatment, patient number, treatment by patient number, and baseline A1C were included, with responder rate as the dependent variable) was fit to the data. The SAS LOGIT procedure was used to conduct the analysis, and significance of the effects was assessed via Wald
The effects of demographic and epidemiologic factors on the primary end point were analyzed using ANCOVA with subgroup, treatment, and patient number as factors and baseline A1C as a covariate. The subgroups were stratified based on age (<65 and
Safety assessments were based on the population of patients who were randomized, received study medication, and had follow-up data. The proportions of patients in each treatment group reporting at least one hypoglycemic event, severe hypoglycemic events, and nocturnal hypoglycemic events were compared across the four study arms via Wald
Study investigators and sites A total of 2,164 investigators participated in the study. Primary care or internal medicine physicians represented 76% of investigators. Less than 10% of the investigators were endocrinologists, and the remaining 14% were categorized as "other specialty" or "unknown." More than half of the 2,164 participating sites (n = 1,255) enrolled the planned four patients each. To compensate for lower recruitment rates at other sites, some sites (n = 190) were permitted to enroll up to eight patients; 235 sites enrolled one patient, and 123 sites enrolled eight patients.
Patient disposition
Patient characteristics Baseline characteristics were comparable across all study arms (Table 2). The racial distribution of the primary analysis population was 71% (4,034) white, 16% (914) black, 10% (587) Hispanic, and 3% (172) other groups. Mean baseline BMI was 34 kg/m2; 60% of patients had a BMI between 28 and 40 kg/m2, and 20% had BMI 40 kg/m2. The mean age was 57 years, with 26% (n = 1,470) of patients aged 65 years. Across the four arms, the mean duration of diabetes was 8.5 years, and 28% of patients had diabetes for >10 years. The mean fasting plasma glucose level was 211 mg/dl and mean laboratory A1C level was 8.9%. Baseline A1C was 9.8% in 25% of patients and was higher among patients who had a lower BMI (9.1% for BMI <28 kg/m2 vs. 8.8% for BMI 28 kg/m2) or were younger (9.0% for those <65 years vs. 8.5% in those 65 years). Patients who were black or Hispanic had higher baseline A1C levels (9.5 and 9.2%, respectively) than white patients (8.7%) (Table 2). The majority of patients (77%) were receiving combination therapy, most commonly a sulfonylurea plus metformin (40%), followed by triple therapy with a sulfonylurea, metformin, and a TZD (18%). The distribution of oral therapy was similar across the four arms (Table 2).
Insulin dose Because all groups followed the same titration algorithm, the insulin dose was titrated weekly and increased in a similar pattern across the study arms; however, the active titration groups consistently had higher doses from week 6 onward. At end point, the average insulin dose in the usual titration groups was 50 IU (interquartile range 2466) compared with 5556 IU (2876) in the active titration groups. The insulin dose at the end of the study was significantly higher in the active titration groups versus the usual titration groups (P < 0.001).
Primary outcome: change in A1C
Secondary outcomes Proportion of patients achieving A1C <7.0%. The proportion of patients achieving the goal A1C <7.0% was 30% for usual titration monitoring groups versus 38% for active titration monitoring groups (P < 0.0001). Within the active titration group, a significantly greater proportion of patients in the POC group achieved the A1C goal than did patients in the laboratory A1C group (41 vs. 36%; P < 0.0001). When stratified by baseline A1C, pairwise comparisons indicated that a baseline A1C <8.5% was associated with the greatest proportion (4550%, across study arms) of patients achieving their A1C goal. In contrast, a baseline A1C >10.0% was associated with only 1427% of patients attaining an A1C <7.0% (Fig. 2). Within the active groups, POC A1C testing significantly increased the proportion of patients who achieved A1C <7.0% for the subgroup of patients whose baseline A1C was >10.0% (P < 0.0021 vs. laboratory A1C testing). Based on model-adjusted estimates at the same baseline A1C, POC testing resulted in a greater proportion of patients achieving the target A1C compared with laboratory testing (for baseline A1C at the 75th percentile [9.7%], P = 0.0387 and for baseline A1C at the 90th percentile [10.7%], P = 0.0423).
Subgroup analysis for A1C. Subgroup analysis revealed that significant reductions in A1C from baseline to end point were observed in all study arms regardless of baseline age, race, BMI, and duration of diabetes. Although greater reductions in A1C were associated with age <65 years, BMI <28 kg/m2, and duration of illness of <5 years, these differences did not reach statistical significance. Medication discontinuation was similar across the four arms, and the change in A1C from baseline to end point was significant regardless of baseline oral antidiabetic medications; however, the subgroup of patients who discontinued TZD and/or metformin therapy at study entry had a higher mean A1C at end point than patients who did not discontinue oral agents.
Change in fasting SMBG.
Hypoglycemia.
Changes in weight and BMI.
Safety and tolerability
This study was designed to determine the impact of active versus usual monitoring of the use of a simple insulin dose titration algorithm and POC versus laboratory A1C testing on glycemic control and whether these strategies could be readily implemented in a predominantly primary care setting for patients with type 2 diabetes who had not achieved glycemic targets with oral antidiabetic therapy. With minimal instruction, patients were able to follow the insulin dose titration algorithm and achieve significant A1C reductions, regardless of the intensity of titration monitoring. All groups showed significant reductions in A1C over 6 months, with significantly greater reductions in the active titration arms compared with the usual titration arms (1.5 vs. 1.3%; P < 0.0001). These A1C reductions are of clinical importance as each 1.0% reduction corresponds to a 35% reduction in the risk of microvascular complications (14) and an 1821% reduction in the risk of cardiovascular events (15,16). Although available time and resources in clinical practice may limit the application of active titration monitoring, this approach provides a significant but marginal benefit and may be considered for patients whose diabetes is most uncontrolled. Significant reductions in A1C were achieved in all study arms regardless of baseline age, race, BMI, or duration of diabetes. Because laboratory A1C testing was done only at the baseline and end-of-study visits for the two POC A1C testing arms, an ITT analysis was not conducted to avoid bias. However, because SMBG was measured at every visit in all four arms, an ITT analysis using LOCF was conducted and demonstrated results consistent with those of the primary analysis population. Active titration with POC A1C testing compared with laboratory testing resulted in a greater proportion of patients achieving the goal A1C of <7.0% (41 vs. 36%; P < 0.0001). Stratification by baseline A1C levels suggested that immediate availability of an A1C result may be more likely to have an impact on glycemic control in patients with higher baseline A1C values (>10.0%). There are several notable differences between the current study and previous reports. More than 2,000 investigators were involved in GOAL A1C, and the majority (75%) were research-naive primary care physicians with busy clinical practices. Because the study assessed methods of monitoring patient management rather than therapeutic interventions, investigator technique had the potential to affect outcomes. However, standardized investigator training sessions and rigorous trial monitoring were implemented to minimize variability. The insulin dosing algorithm was less aggressive than that in previous studies (2) to minimize the potential of hypoglycemia; nevertheless, the algorithm resulted in average daily insulin doses of at least 50 IU in all four treatment arms within 6 months. Although obtaining complete glucose profiles would have been ideal for assessing pre- and postprandial glucose control and hypoglycemia (especially asymptomatic episodes), we felt that, for the addition of basal insulin treatment in this patient population, limiting monitoring to one test daily before breakfast would encourage greater compliance with the protocol. Overall, the approach and outcomes in the large nationwide patient sample represented in the GOAL A1C study may more closely reflect what can be anticipated with the adoption of a similar insulin algorithm in primary care clinical practices attended by most patients with type 2 diabetes in the U.S. In general, the immediate availability of an A1C value at the clinic visit (POC testing) did not have any additional impact on glycemic control beyond active titration. This could be because insulin dose titration was primarily driven by a fasting SMBG target <100 mg/dl, which may correlate with A1C <7% (17). In addition, the POC testing device was not certified by the National Glycohemoglobin Standardization Program at the time of this study, and a post hoc analysis revealed poor precision of the POC A1C methodology when baseline POC A1C results were compared with the baseline laboratory A1C results; this lack of precision may have resulted in diminished investigator reliance on POC A1C results (18).
The overall safety profile of insulin glargine was similar to or better than that observed in prior studies of insulin therapy in type 2 diabetes (2,19). Riddle et al. (2) reported a rate of hypoglycemia (<70 mg/dl) of 9 and 13 events/patient-year for the glargine and neutral protamine Hagedorn insulin groups, respectively. Rates of severe events were In summary, the GOAL A1C study demonstrates that basal insulin glargine treatment can be initiated with ease in a predominantly primary care setting using a simple titration algorithm and safely results in significant A1C reduction. Addition of basal insulin therapy should be considered in all patients with type 2 diabetes previously uncontrolled with oral antidiabetic agents alone. Weekly monitored (active) insulin titration resulted in significant improvement in glycemic control compared with every 6 weeks monitored (usual) titration. POC A1C may have an additional impact compared with laboratory monitoring among patients with baseline A1C >10.0%. Regardless of study arm, the majority of patients achieved significant and clinically important improvements in glycemic control.
Implementation of titration algorithm Dose titration table. The starting dose was 10 IU administered subcutaneously at bedtime. Titration occurred weekly according to the fasting SMBG value based on the mean of the last 24 days morning fasting SMBG values. Adjustments to the daily basal insulin dose were made every 7 days based on fasting SMBG as shown in Table 1A.
Patient instruction at baseline.
Standardization procedures The protocol, case report forms, and study procedures were reviewed and discussed at identically structured meetings across the U.S. In addition, 350 investigators who were unable to attend a meeting were provided with a Web-based training session. After these investigator training sessions and before the shipment of study supplies, phone calls were made to each site to clarify any issues relating to the protocol, procedure, or supplies. Most study monitoring was coordinated and conducted through a call center. All titration sheets were forwarded to a central study coordinator (ParExel) for review. On-site monitoring visits were made only to sites that had reported a serious adverse event or were found to be noncompliant to monitoring calls. Laboratory tests were performed by a National Glycohemoglobin Standardization Programcertified centralized laboratory (Quest Diagnostics Clinical Trials).
Statistical methods Assessment of potential carryover effect, period effect, and study arm interaction. The potential for a carryover effect (as an investigators experience with one study arm might influence the outcome in subsequent study arms) was examined using ANCOVA with treatment, previous number of patients enrolled at a given site, and effect of prior treatments as factors and baseline A1C as covariate. Only the first four patients enrolled at a site were included in the analysis. The possibility of a period effect (i.e., cumulative experience might improve investigator proficiency and possibly improve outcomes) was also addressed by using ANCOVA, applying the SAS generalized linear models procedure to compare changes in A1C among the study arms. The model included treatment and patient number as factors, treatment by patient number and treatment by baseline interactions, and baseline A1C as covariate. If the treatment by baseline interaction was not statistically significant, it was dropped from the model. In contrast, the treatment by patient number interaction remained in the model regardless of its significance/lack of significance. The significance of model effects was assessed using type III sums of squares. Pairwise comparisons of treatment effects, based on least squares means, were conducted. A secondary analysis was conducted to determine whether there was an interaction between the method of capture for A1C and the type of titration monitoring. This analysis was conducted using ANCOVA with method of capture of A1C, type of titration monitoring, and patient number as factors; A1C method of capture by type of titration monitoring interaction; and baseline A1C as covariate.
This study was sponsored by Aventis Pharmaceuticals, a member of the sanofi-aventis Group, which was involved in design, conduct, data collection, and analysis. The primary authors participated in design and monitoring, controlled data evaluation/interpretation, and prepared the manuscript. Data from this study were presented in poster form at the 65th annual meeting of American Diabetes Association, San Diego, California, 1014 June 2005.
L.K. has served on advisory boards for sanofi-aventis and has received honoraria from sanofi-aventis, Pfizer, GlaxoSmithKline, Novo Nordisk, Takeda, and Eli Lilly. W.H.H. has received honoraria and consulting fees from Aventis Pharmaceuticals. A table elsewhere in this issue shows conventional and Système International (SI) units and conversion factors for many substances. The costs of publication of this article were defrayed in part by the payment of page charges. The article must therefore be hereby marked "advertisement" in accordance with 18 U.S.C. Section 1734 solely to indicate this fact. Received for publication June 9, 2005. Accepted for publication October 6, 2005.
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