Cohort studyindependent cross-checkabstract checked★ key study I-INS-103 in-depth review
Blood sugar control and death in type 1 diabetes in Sweden
Glycemic control and excess mortality in type 1 diabetes.
Overview
Lind M et al.. N Engl J Med 2014 · PMID 25409370 · DOI 10.1056/NEJMoa1408214
People with type 1 diabetes died about 3.5 times as often as matched controls; with very high HbA1c the risk was about 8.5 times higher.
Does the study support the specific claim? No · Methodological quality: high
Plain-language summary
Study explained simply
- What did the researchers want to find out?
Measure excess mortality in T1D by glucose control.
- How was the study done?
Nationwide register with matched controls.
- How many people, animals or samples were studied?
33,915 patients, 169,249 controls.
- What was actually found?
Higher HbA1c, higher death risk; excess risk even with good control.
- How large was the observed effect?
HR 3.52 overall; 8.51 at HbA1c >=9.7%.
- What do the results mean in everyday life?
Type 1 diabetes shortens life, especially with high sugar.
- What are the study's limitations?
Observational data.
- What does it say about Elawady's specific claim?
Contradicts denial of T1D complications and 'high sugar protects'.
- Do the results apply to Germany and Europe?
Swedish data, directly applicable to Europe.
- What can explicitly not be concluded from this study?
Cannot prove that lowering HbA1c alone removes all excess risk.
Scientific in-depth review
1. Full reference
- Authors
- Lind M et al.
- Journal
- N Engl J Med
- Year
- 2014
- Identifier
- PMID 25409370 DOI 10.1056/NEJMoa1408214
- Verification
- verified – PubMed efetch 2026-10-26; Crossref 2026-10-26
- Retracted
- no
- Corrections
- none
- Extent checked
- abstract only
- Conflicts of interest and funding
Funded by the Swedish Society of Medicine and others (abstract).
2. Research question
What is the excess mortality in T1D by level of glycaemic control?
3. Study design and population
- Study design
- Cohort study – Registry-based matched cohort (Swedish National Diabetes Register), 5 controls per patient
- Population
Patients with T1D registered from 1998 and matched population controls
- Country
Sweden
- Period
1998-2011
- Sample size
33,915 patients; 169,249 controls
- Inclusion and exclusion criteria
T1D in the National Diabetes Register after 1 January 1998
4. Methods and endpoints
- Exposure / intervention
T1D, categorised by HbA1c
- Comparator
Matched general-population controls
- Endpoints
All-cause and cardiovascular death
- Statistical methods
Multivariable Cox models
5. Actual results
- Results
Deaths 2701/33,915 (8.0%) vs 4835/169,249 (2.9%); adjusted HR 3.52 (95% CI 3.06-4.04); CV death 2.7% vs 0.9%, HR 4.60 (3.47-6.10). By HbA1c: <=6.9% HR 2.36 (1.97-2.83); 7.0-7.8% 2.38 (2.02-2.80); 7.9-8.7% 3.11 (2.66-3.62); 8.8-9.6% 3.65 (3.11-4.30); >=9.7% 8.51 (7.24-10.01).
- Absolute risks
Crude death 8.0% vs 2.9% over about 8 years
- Authors' conclusion
Even with HbA1c <=6.9%, people with T1D had twice the risk of death of matched controls.
6. Strengths
- Nationwide, large
- Matched controls
- Dose-response by HbA1c
7. Weaknesses
- Observational
- Residual confounding
- HbA1c at baseline/updated only as registry allows
8. Risk of bias
- Orienting tool
- ROBINS-E
- Type of assessment
- simplified assessment (abstract only)
- Full formal assessment
- no
- Overall risk of bias
- some concerns
- Rationale
Observational; strong gradient by HbA1c and large effect sizes make confounding an unlikely full explanation.
9. Assessment of the statistical interpretation
Hazard ratios; CIs log-symmetric (stats/C-INS-07_t1d_mortality.py). Clear gradient with HbA1c.
10. Relevance to the specific claim
People with T1D do suffer cardiovascular complications and premature death, rising steeply with poor control; refutes 'type 1 patients do not develop complications' and 'high sugar is protective'.
11. Independent contrary findings
12. Transferability to Germany and Europe
Directly applicable; same biology and clinical standards in Europe.
13. Overall methodological judgement
High-quality registry evidence.
| Multidimensional assessment | |
|---|---|
| Authenticity of the source | verified |
| Methodological quality | high |
| Risk of bias | some concerns |
| Precision of results | high |
| Directness | direct |
| Reproducibility | replicated |
| Consistency with the overall evidence | consistent |
| Regional transferability | high |
| Adequacy of the interpretation (by the archive) | not applicable |
14. Open questions
15. Linked fact checks
- There is no such thing as type 1 diabetes; 'type 1' is a state of high sugar seen mainly in athletes with high needs; type 1 patients do not develop complications; insulin before puberty is a catastrophe (short stature, thyroid problems, cysts). – Studies contradicting or limiting the claim
- High blood sugar is not a disease but the body's protective response that 'rescues' you; there is no such thing as diabetes ('drink sugar'); sugar intake has no upper limit; HbA1c is a lie. – Studies contradicting or limiting the claim