Records after duplicates removed (n = 2274) Records screened (n = 2274) Full-text articles assessed for eligibility (n = 16)

Size: px

Start display at page:

Download "Records after duplicates removed (n = 2274) Records screened (n = 2274) Full-text articles assessed for eligibility (n = 16)"

Thomasine Anthony
5 years ago
Views:

1 Supplemental Figure 1 Adapted from Prisma Flow Chart Records identified through database searching (n = 3093) Additional records identified through other sources (n = 2) Records after duplicates removed (n = 2274) Records screened (n = 2274) Records excluded based on title and abstract (n = 2258) Full-text articles assessed for eligibility (n = 16) Published studies contacted for IPD-analysis (n = 6) Full-text articles excluded (n = 10) - Poster, conference abstract or cohort description paper (n = 4) - No euthyroid comparison group (n = 4) - Cross-sectional design and no specific stroke outcomes (n = 1) - Review (n = 1) Declined to participate (n = 1) Published studies included in IPD-analysis (n = 5) Unpublished studies identified through experts (n = 1) Studies included in IPD-analysis (n = 17) Unpublished studies included through the Thyroid Studies Collaboration (n = 11) Unpublished studies identified through the Thyroid Studies Collaboration (n = 12) Study excluded due to lack of outcome events (n = 1)

2 Supplemental Table 1 Definitions of Subclinical Hypothyroidism, Stroke and Proportion of Missing Data Study name & Reference 4D Study 2 Birmingham Study 3 Subclinical hypothyroidism Total and free T4 Reference values a ft pmol/l Proportion missing (F)T4 in subclinical hypothyroidism (%) Stroke definition Proportion of missing data for covariates b (%) 0 Adjudicated first stroke event and death from stroke 0.0 or missing ft pmol/l 20/92 (21.7) Cerebrovascular diseases (ICD ) NA 4 Brazilian Thyroid Study ft ng/dl 0 Busselton Health Study 5 ft pmol/l 1/89 (1.1) or missing Cardiovascular Health Study 6 EPIC-Norfolk Study 7 Health, Aging, and Body Composition Study 8 or missing ft pmol/l 21/492 (4.3) or missing ft pmol/l 0 ft pmol/l Recoded according to cause of death( ICD-9 codes ) First stroke event and death from stroke ICD-9 codes (& ICD 10 I60-I69 including G45) Adjudicated hospitalization for stroke, or death from stroke Cerebrovascular diseases ( , I60-I69) on hospital discharge, or as underlying cause of death, excl. TIA 230/335 (68.7) Adjudicated first stroke event and death from stroke InCHIANTI Study 9 Leiden 85-plus Study 10 MrOS Study 11 Nagasaki Adult Health Study 12 Pisa cohort 13 PREVEND 14 PROSPER Trial 15 ft ng/dl 0 ft pmol/l 1/35 (2.9) or missing ft ng/dl 0 Recoded according to cause of death( ICD-9 codes ), local ascertainment for stroke events Adjudicated first stroke event and/or death (ICD-10 I60-I69) Death certificates used from start of study. Adjudicated death from stroke according to ICD9 codes from the years onward ft Stroke specific mortality (ICD ) 6.3 pmol/l ft ng/dl 0 Recoded according to cause of death 6.2 ft Stroke event and/or death (ICD-10 I60-I69), excl pmol/l TIA ft pmol/l 241/446 (54.0) Adjudicated first stroke event and death from stroke 0.0 or missing

3 Supplemental Table 1 Definitions of Subclinical Hypothyroidism, Stroke and Proportion of Missing Data - Continued Study name & Reference Rotterdam Study 16,17 SHIP 18 Subclinical hypothyroidism Total and free T4 Reference values a Proportion missing (F)T4 in subclinical hypothyroidism (%) or missing ft pmol/l 32/104 (30.8) Stroke definition Adjudicated first stroke event and death from stroke (ICD-10 I60-I69) Proportion of missing data for covariates b (%) ft pmol/l 0 Self-reported stroke by questionnaire Whickham Survey 19 TSH 6.0 & <21.5 mu/l and T4 in or missing Total T nmol/l 2/ 128 (1.6) Stroke specific mortality (ICD ) and incident events 1.5 Abbreviations: TSH, Thyroid-Stimulating-Hormone; T4: thyroxine; ft4: free thyroxine; NA not applicable a To convert free T4 from pmol/l to ng/dl, divide by To convert total T4 from nmol/l to μg/dl, divide by b Missingness of the covariates of smoking, systolic blood pressure, total cholesterol and history of diabetes combined

4 Supplemental Table 2. Sensitivity Analyses for the association between Subclinical Hypothyroidism and the Risk of Stroke Events and Fatal Stroke a Stroke events b Fatal Stroke No. Events/Participants HR (95% CI) No. Events/Participants HR (95% CI) Random-effects Model 2547/37, (0.91, 1.21) 1014/47, (0.80, 1.42) Fixed-effects Model 2547/37, (0.92, 1.21) 1014/47, (0.90, 1.37) Excluding those with a history of stroke c 2133/34, (0.90, 1.24) 812/39, (0.80, 1.46) Excluding those with missing (F)T4 d 1606/28, (0.96, 1.40) 706/36, (0.86, 1.59) Excluding those with thyroid medication use at baseline Excluding thyroid medication use at baseline and follow up 2475/37, (0.92, 1.22) 993/46, (0.86, 1.51) 1585/21, (0.70, 1.31) 656/27, (0.74, 2.16) Only studies with formal adjudication procedures e 1245/ (0.82, 1.14) 514/14, (0.64, 1.27) Additional multivariate analyses f Multivariate unimputed data 2511/37, (0.77, 1.22) 949/45, (0.82, 1.51) Multivariate + BMI g 2547/37, (0.91, /46, (0.82, 1.56) Multivariate + lipid lowering and antihypertensive medication 1815/25, (0.86, 1.17) 725/30, (0.64, 1.44)

5 Supplemental Table 2. Sensitivity Analyses for the association between Subclinical Hypothyroidism and the Risk of Stroke Events and Fatal Stroke a (Continued) Stroke events b Fatal Stroke No. Events/Participants HR (95% CI) No. Events/Participants HR (95% CI) Studies excluded Diabetes and dialysis patients study - 4D 2480/36, (0.91, 1.21) 987/46, (0.79, 1.42) Cardiac patients study Pisa NA NA 988/44, (0.74, 1.40) Atomic Bomb Survivors Nagasaki NA NA 942/44, (0.77, 1.39) Clinical Trial Prosper 2289/32, (0.92, 1.23) 982/42, (0.82, 1.45) Stroke assessed by questionnaire SHIP 2477/34, (0.91, 1.20) 982/44, (0.84, 1.34) Studies including TIAs as stroke events Busselton Three studies with no events in exposure group MrOs, PREVEND, 4D Studies without community dwelling adults 4D, Pisa,PROSPER 2349/35, (0.90, 1.21) 968/45, (0.77, 1.41) 2428/34, (0.90, 1.22) 953/42, (0.79, 1.45) 2222/31, (0.89, 1.25) 929/37, (0.77, 1.42) Including not participating study /38, (0.91, 1.20) NA NA Abbreviations: HR, hazard ratio; CI, Confidence Interval; (F)T4, free thyroxine; NA, not applicable; TIA, transient ischemic attack. a The HRs were adjusted for age and sex. b Data were available from 12 studies. c Excluding Birmingham Study and Busselton Health Study due to missing data on stroke at baseline. d Excluding participants in the fatal stroke analysis, and 9513 participants in the stroke events analysis (Supporting information).

6 e Formal adjudication procedure is defined as having clear criteria for the outcomes that were reviewed by experts for each potential case. This was the case for the stroke events analysis in Cardiovascular Health Study, Health ABC Study, Leiden 85-plus Study, Rotterdam Study, 4D Study and Prosper Trial and for the fatal stroke analysis additional in MrOs Study and Pisa Cohort. f The Birmingham Study was excluded from the multivariable analyses because of lack of data on cardiovascular risk factors. Multivariate analyses included adjustments for sex, age, systolic blood pressure, smoking and prevalent diabetes at baseline. Data on lipid-lowering and hypertensive medications were not available for EPIC-Norfolk and the Nagasaki Adult Health Study. g Body Mass Index defined as weight (kg) divided by height (m) squared.

7 References 1. Chaker L, Baumgartner C, Ikram MA, et al. Subclinical Thyroid Dysfunction and the Risk of Stroke: a Systematic Review and Meta-Analysis European Journal of Epidemiology Drechsler C SA, Gutjahr-Lengsfeld L, Kroiss M, Carrero JJ, Krane V, Allolio B, Wanner C, Fassnacht M. Thyroid Function, Cardiovascular Events, and Mortality in Diabetic Hemodialysis Patients. Am J Kidney Dis Parle JV, Maisonneuve P, Sheppard MC, Boyle P, Franklyn JA. Prediction of all-cause and cardiovascular mortality in elderly people from one low serum thyrotropin result: a 10-year cohort study. Lancet. Sep ;358(9285): Sgarbi JA, Matsumura LK, Kasamatsu TS, Ferreira SR, Maciel RM. Subclinical thyroid dysfunctions are independent risk factors for mortality in a 7.5-year follow-up: the Japanese-Brazilian thyroid study. European Journal of Endocrinology. Mar 2010;162(3): Walsh JP, Bremner AP, Bulsara MK, et al. Subclinical thyroid dysfunction as a risk factor for cardiovascular disease. Archives of Internal Medicine. Nov ;165(21): Cappola AR, Fried LP, Arnold AM, et al. Thyroid status, cardiovascular risk, and mortality in older adults. JAMA. Mar ;295(9): Boekholdt SM, Titan SM, Wiersinga WM, et al. Initial thyroid status and cardiovascular risk factors: the EPIC-Norfolk prospective population study. Clinical Endocrinology. Mar 2010;72(3): Rodondi N, Newman AB, Vittinghoff E, et al. Subclinical hypothyroidism and the risk of heart failure, other cardiovascular events, and death. Archives of Internal Medicine. Nov ;165(21): Ferrucci L, Bandinelli S, Benvenuti E, et al. Subsystems contributing to the decline in ability to walk: bridging the gap between epidemiology and geriatric practice in the InCHIANTI study. Journal of the American Geriatrics Society. Dec 2000;48(12): Gussekloo J, van Exel E, de Craen AJ, Meinders AE, Frolich M, Westendorp RG. Thyroid status, disability and cognitive function, and survival in old age. JAMA. Dec ;292(21): Waring AC, Harrison S, Samuels MH, et al. Thyroid function and mortality in older men: a prospective study. Journal of Clinical Endocrinology & Metabolism. Mar 2012;97(3): Imaizumi M, Akahoshi M, Ichimaru S, et al. Risk for ischemic heart disease and all-cause mortality in subclinical hypothyroidism. Journal of Clinical Endocrinology & Metabolism. Jul 2004;89(7): Iervasi G, Molinaro S, Landi P, et al. Association between increased mortality and mild thyroid dysfunction in cardiac patients. Archives of Internal Medicine. Jul ;167(14): Hillege HL, Janssen WM, Bak AA, et al. Microalbuminuria is common, also in a nondiabetic, nonhypertensive population, and an independent indicator of cardiovascular risk factors and cardiovascular morbidity. Journal of Internal Medicine. Jun 2001;249(6): Nanchen D, Gussekloo J, Westendorp RG, et al. Subclinical thyroid dysfunction and the risk of heart failure in older persons at high cardiovascular risk. Journal of Clinical Endocrinology & Metabolism. Mar 2012;97(3):

8 16. Hak AE, Pols HA, Visser TJ, Drexhage HA, Hofman A, Witteman JC. Subclinical hypothyroidism is an independent risk factor for atherosclerosis and myocardial infarction in elderly women: the Rotterdam Study. Annals of Internal Medicine. Feb ;132(4): Hofman A, Darwish Murad S, van Duijn CM, et al. The Rotterdam Study: 2014 objectives and design update. European Journal of Epidemiology. Nov 2013;28(11): Ittermann T, Haring R, Sauer S, et al. Decreased serum TSH levels are not associated with mortality in the adult northeast German population. European Journal of Endocrinology. Mar 2010;162(3): Razvi S, Weaver JU, Vanderpump MP, Pearce SH. The incidence of ischemic heart disease and mortality in people with subclinical hypothyroidism: reanalysis of the Whickham Survey cohort. Journal of Clinical Endocrinology & Metabolism. Apr 2010;95(4): Schultz M, Kistorp C, Raymond I, et al. Cardiovascular events in thyroid disease: a population based, prospective study. Hormone & Metabolic Research. Aug 2011;43(9):

9 PRISMA 2009 Checklist Supplemental Table 3 Section/topic TITLE # Checklist item Title 1 Identify the report as a systematic review, meta-analysis, or both. 1 ABSTRACT Structured summary 2 Provide a structured summary including, as applicable: background; objectives; data sources; study eligibility criteria, participants, and interventions; study appraisal and synthesis methods; results; limitations; conclusions and implications of key findings; systematic review registration number. INTRODUCTION Rationale 3 Describe the rationale for the review in the context of what is already known. 5 Objectives 4 Provide an explicit statement of questions being addressed with reference to participants, interventions, comparisons, outcomes, and study design (PICOS). METHODS Protocol and registration 5 Indicate if a review protocol exists, if and where it can be accessed (e.g., Web address), and, if available, provide registration information including registration number. Eligibility criteria 6 Specify study characteristics (e.g., PICOS, length of follow-up) and report characteristics (e.g., years considered, language, publication status) used as criteria for eligibility, giving rationale. Information sources 7 Describe all information sources (e.g., databases with dates of coverage, contact with study authors to identify additional studies) in the search and date last searched. Search 8 Present full electronic search strategy for at least one database, including any limits used, such that it could be repeated. Study selection 9 State the process for selecting studies (i.e., screening, eligibility, included in systematic review, and, if applicable, included in the meta-analysis). Data collection process 10 Describe method of data extraction from reports (e.g., piloted forms, independently, in duplicate) and any processes for obtaining and confirming data from investigators. Data items 11 List and define all variables for which data were sought (e.g., PICOS, funding sources) and any assumptions and simplifications made. Risk of bias in individual studies 12 Describe methods used for assessing risk of bias of individual studies (including specification of whether this was done at the study or outcome level), and how this information is to be used in any data synthesis. Summary measures 13 State the principal summary measures (e.g., risk ratio, difference in means). 7&8 Reported on page # 4 5 NA 6 6 &Sup. Mat. Sup. Mat. 6&7 6& &9

10 PRISMA 2009 Checklist Synthesis of results 14 Describe the methods of handling data and combining results of studies, if done, including measures of consistency (e.g., I 2 ) for each meta-analysis. 8&9 Section/topic # Checklist item Page 1 of 2 Risk of bias across studies 15 Specify any assessment of risk of bias that may affect the cumulative evidence (e.g., publication bias, selective reporting within studies). Additional analyses 16 Describe methods of additional analyses (e.g., sensitivity or subgroup analyses, meta-regression), if done, indicating which were pre-specified. RESULTS Study selection 17 Give numbers of studies screened, assessed for eligibility, and included in the review, with reasons for exclusions at each stage, ideally with a flow diagram. Study characteristics 18 For each study, present characteristics for which data were extracted (e.g., study size, PICOS, follow-up period) and provide the citations. Reported on page # 9& , Figure S1 10, Table 1 Risk of bias within studies 19 Present data on risk of bias of each study and, if available, any outcome level assessment (see item 12). Tab 2 & Fig 1 Results of individual studies 20 For all outcomes considered (benefits or harms), present, for each study: (a) simple summary data for each intervention group (b) effect estimates and confidence intervals, ideally with a forest plot. Figure 1 Synthesis of results 21 Present results of each meta-analysis done, including confidence intervals and measures of consistency. Tab 2 & Fig. 1 Risk of bias across studies 22 Present results of any assessment of risk of bias across studies (see Item 15). 11 & 12, Fig. 1 Additional analysis 23 Give results of additional analyses, if done (e.g., sensitivity or subgroup analyses, meta-regression [see Item 16]). 10&11,Tab 2, Tab 3. DISCUSSION Summary of evidence 24 Summarize the main findings including the strength of evidence for each main outcome; consider their relevance to key groups (e.g., healthcare providers, users, and policy makers). Limitations 25 Discuss limitations at study and outcome level (e.g., risk of bias), and at review-level (e.g., incomplete retrieval of identified research, reporting bias). Conclusions 26 Provide a general interpretation of the results in the context of other evidence, and implications for future research. 16&17 FUNDING Funding 27 Describe sources of funding for the systematic review and other support (e.g., supply of data); role of funders for the systematic review. From: Moher D, Liberati A, Tetzlaff J, Altman DG, The PRISMA Group (2009). Preferred Reporting Items for Systematic Reviews and Meta-Analyses: The PRISMA Statement. PLoS Med 6(6): e

11 PRISMA 2009 Checklist doi: /journal.pmed For more information, visit: Page 2 of 2

Supplementary Online Material

Supplementary Online Material Collet T-H, Gussekloo J, Bauer DC, et al; Thyroid Studies Collaboration. Subclinical hyperthyroidism and the risk of coronary heart disease and mortality. Arch Intern Med.