4.3.0.0 Real-‍time Con­tin­u­ous Glu­cose Mon­i­tor Use in Adults

Data exist to sup­port the use of CGM in adults, both those on MDI and on CSII. In terms of ran­dom­ized con­trolled tri­als in peo­ple with type 1 di­a­betes, there are four stud­ies in adults with A1C as the pri­ma­ry out­come (80–84), three stud­ies in adults with hy­po­glycemia as the pri­ma­ry out­come (85–87), four stud­ies in adults and chil­dren with A1C as the pri­ma­ry out­come (41,64–66), and three stud­ies in adults and chil­dren with hy­po­glycemia as a pri­ma­ry out­come (41,78,,88). There are three stud­ies in adults with type 1 or type 2 di­a­betes (89–91) and four stud­ies with adults with type 2 di­a­betes (92–95). Fi­nal­ly, there are three stud­ies that have been done in preg­nant women with prepreg­nan­cy di­a­betes or ges­ta­tion­al di­a­betes mel­li­tus (96–98). Over­all, ex­clud­ing stud­ies eval­u­at­ing pe­di­atric pa­tients alone or preg­nant women, 2,984 peo­ple with type 1 or type 2 di­a­betes have been stud­ied to as­sess the benefits of CGM.

Pri­ma­ry Out­come: A1C Re­duc­tion

In gen­er­al, A1C re­duc­tion was shown in stud­ies where the base­line A1C was high­er. In two larg­er stud­ies in adults with type 1 di­a­betes that as­sessed the benefit of CGM in pa­tients on MDI, there were significant re­duc­tions in A1C: -0.6% in one (80,81) and -0.43% in the other (82). No re­duc­tion in A1C was seen in a small study per­formed in un­der­served, less well-‍ed­u­cat­ed adults with type 1 di­a­betes (83). In the adult sub­set of the JDRF CGM study, there was a significant re­duc­tion in A1C of -0.53% (71) in pa­tients who were pri­mar­i­ly treat­ed with in­sulin pump ther­a­py. Bet­ter ad­her­ence in wear­ing the CGM de­vice re­sulted in a greater like­li­hood of an im­provement in glycemic con­trol (41,84).

Stud­ies in peo­ple with type 2 di­a­betes are het­ero­ge­neous in de­signd in two, par­tic­i­pants were using basal in­sulin with oral agents or oral agents alone (65,95); in one, in­di­vid­u­als were on MDI alone (92); and in an­oth­er, par­tic­i­pants were on CSII or MDI (79). The find­ings in stud­ies with MDI alone (92) and in two stud­ies in peo­ple using oral agents with or with­out in­sulin (93,95) showed significant re­duc­tions in A1C lev­els.

Pri­ma­ry Out­come: Hy­po­glycemia

In stud­ies in adults where re­duc­tion in episodes of hy­po­glycemia was the pri­ma­ry end point, significant re­duc­tions were seen in in­di­vid­u­als with type 1 di­a­betes on MDI or CSII (85–87). In one study in pa­tients who were at high­er risk for episodes of hy­po­glycemia (87), there was a re­duc­tion in rates of all lev­els of hy­po­glycemia (see Sec­tion 6 “Glycemic Tar­gets” for hy­po­glycemia defini­tions). The Mul­ti­ple Daily In­jec­tions and Con­tin­u­ous Glu­cose Mon­i­toring in Di­a­betes (DI­A­MOND) study in peo­ple with type 2 di­a­betes on MDI did not show a re­duc­tion in hy­po­glycemia (92). Stud­ies in in­di­vid­u­als with type 2 di­a­betes on oral agents with or with­out in­sulin did not show re­duc­tions in rates of hy­po­glycemia (93,95). CGM may be par­tic­u­larly use­ful in in­sulin-‍treat­ed pa­tients with hy­po­glycemia un­aware­ness and/‍or fre­quent hy­po­glycemic episodes, al­though stud­ies have not shown con­sistent re­duc­tions in se­vere hy­po­glycemia (41,64,,65).

Sen­sor-‍aug­ment­ed pumps that sus­pend in­sulin when glu­cose is low or pre­dict­ed to go low with­in the next 30 min have been ap­proved by the FDA. The Au­toma­tion to Sim­u­late Pan­cre­at­ic In­sulin Re­sponse (AS­PIRE) trial of 247 pa­tients with type 1 di­a­betes and doc­u­ment­ed noc­tur­nal hy­po­glycemia showed that sen­sor-‍aug­ment­ed in­sulin pump ther­a­py with a low-‍glu­cose sus­pend func­tion significant­ly re­duced noc­tur­nal hy­po­glycemia over 3 months with­out in­creas­ing A1C lev­els (66). In a dif­fer­ent sen­sor-‍aug­ment­ed pump, pre­dic­tive low-‍glu­cose sus­pend re­duced time spent with glu­cose <70 mg/dL from 3.6% at base­line to 2.6% (3.2% with sen­sor-‍aug­ment­ed pump ther­a­py with­out pre­dic­tive low glu­cose sus­pend) with­out re­bound hy­per­glycemia dur­ing a 6-week ran­dom­ized crossover trial (95a). These de­vices may offer the op­por­tu­ni­ty to re­duce hy­po­glycemia for those with a his­to­ry of noc­tur­nal hy­po­glycemia.