Nehrling 1985.

Study characteristics
Methods	Study design: parallel randomised controlled trial
Participants	Inclusion criteria: age 18 to 65 years type 1 or type 2 diabetes fasting plasma glucose not > 200 mg/dL at the time of study entry stable therapy (no change of medication or dosage) for at least 1 month Exclusion criteria: — Diagnostic criteria: diagnosis of diabetes had been established by a fasting plasma glucose > 140 mg/dL, an abnormal oral glucose tolerance test as interpreted by the US Public Health Service criteria, or an unequivocal history of diabetes; insulin‐dependent diabetes mellitus: participants who, by history, developed ketosis or ketoacidosis when adequate exogenous insulin was not provided; non‐insulin‐dependent diabetes mellitus: individuals who are not on insulin and are not ketotic or who, if on insulin, have no history of ketoacidosis Setting: presumably outpatients Age group: adults Sex: not reported, but probably females and males Country where trial was performed: USA
Interventions	Intervention(s): aspartame 2.7 g daily, in capsules Comparator(s): placebo capsules containing cornstarch, 1.8 g daily Duration of intervention: 18 weeks Duration of follow‐up: 18 weeks Run‐in period: 1 week Number of study centres: 1
Outcomes	Reported outcomes in full text of publication: HbA1c, adverse events, glucose levels (fasting and postprandial)
Identification	Trial identifier: — Trial terminated early: no
Publication details	Language of publication: English Funding: commercial funding: GD Searle & Co., Skokie, Illinois, and non‐commercial funding: University of Illinois Publication status: peer‐reviewed journal and full article
Stated aim for study	Quote from publication: "... subjects having either insulin‐dependent or non‐insulin‐dependent diabetes completed a randomised, double‐blind study comparing effects of aspartame or a placebo on blood glucose control"
Notes
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Quote from publication: "Capsules were provided in coded bottles, which contained either aspartame or placebo according to a randomization table, and were assigned to subjects in sequential order" Comment: random number tables are an adequate method to generate the allocation sequence
Allocation concealment (selection bias)	Low risk	Quote from publication: "Capsules were provided in coded bottles, which contained either aspartame or placebo according to a randomization table, and were assigned to subjects in sequential order" Comment: the method used ensured that intervention allocation could not have been foreseen in advance or changed after assignment
Blinding of participants and personnel (performance bias) adverse events	Low risk	Quote from publication: "identical appearing placebo capsules" were used Comment: self‐reported outcome
Blinding of participants and personnel (performance bias) glucose levels	Low risk	Quote from publication: "identical appearing placebo capsules" were used Comment: fasting and postprandial glucose levels; investigator‐assessed outcome
Blinding of participants and personnel (performance bias) HbA1c	Low risk	Quote from publication: "identical appearing placebo capsules" were used Comment: investigator‐assessed outcome
Blinding of outcome assessment (detection bias) adverse events	Low risk	Quote from publication: "identical appearing placebo capsules" were used Comment: outcome assessors (i.e. participants) were blinded; self‐reported outcome
Blinding of outcome assessment (detection bias) glucose levels	Low risk	Comment: the outcome measurement is unlikely to have been influenced by lack of blinding; investigator‐assessed outcome
Blinding of outcome assessment (detection bias) HbA1c	Low risk	Comment: the outcome measurement is unlikely to have been influenced by lack of blinding; investigator‐assessed outcome
Incomplete outcome data (attrition bias) adverse events	Low risk	Quote from publication: "Of the 63 subjects, 62 completed the study." Comment: the only dropout was because of an adverse event (gastrointestinal symptoms). Types and numbers of adverse reactions are also clearly stated for participants who completed the study.
Incomplete outcome data (attrition bias) glucose levels	Unclear risk	Comment: only 1 participant dropped out during the study from the aspartame group; dropout rate: 1.6%; the table containing fasting plasma glucose results does not report on sample sizes, i.e. it is unclear whether the data shown are for the 62 participants who completed the study
Incomplete outcome data (attrition bias) HbA1c	Unclear risk	Comment: only 1 participant dropped out during the study from the aspartame group; dropout rate: 1.6%; the table containing HbA1c results does not report on sample sizes, i.e. it is unclear whether the data shown are for the 62 participants who completed the study
Selective reporting (reporting bias)	Low risk	Comment: the study protocol is unavailable, but based on ORBIT classification all expected outcomes seem to have been included in the publication
Other bias	Unclear risk	Comment: the study was supported in part by a commercial grant