Assessment of Cardio Metabolic Profile in Newly Diagnoded Cases of Hypothyroism

Pandey S, Dhaneria S, Banzal S and Chouhan J

Published on: 2025-10-25

Abstract

Background: Hypothyroidism is associated with dyslipidaemia and cardiovascular involvement detectable on ECG and echocardiography, yet contemporary Indian data comparing overt and subclinical disease are limited.

Objectives: To assess the cardio-metabolic profile of newly diagnosed adults with hypothyroidism and compare ECG, echocardiographic abnormalities, and lipid parameters between overt and subclinical hypothyroidism.

Methods: Hospital-based cross-sectional study at a tertiary centre in central India (January–June 2025). Adults (≥18 years) with newly diagnosed primary hypothyroidism were enrolled after exclusions. Overt hypothyroidism was defined as TSH >10 µIU/mL with low T4; subclinical as TSH 4.2–10 µIU/mL with normal T4. All participants underwent 12-lead ECG, transthoracic echocardiography, and fasting lipid profile (TC, LDL-C, HDL-C, TG). Continuous variables were summarised as mean ± SD; categorical as n (%). Group differences used t-test/Mann-Whitney and χ²/Fisher’s exact tests; p<0.05 significant. Ethics approval and informed consent were obtained.

Results: Of 100 participants, 66 had overt and 34 subclinical hypothyroidism; 72% were female. Diastolic dysfunction was present in 62% overall (mild 28%, moderate 24%, severe 10%), systolic dysfunction in 18%, and pericardial effusion in 20%. Diastolic dysfunction severity differed between groups (none: 57.6% overt vs 35.3% subclinical; p=0.007), whereas systolic dysfunction did not (15.2% vs 23.5%; p=0.155). Pericardial effusion trended higher in overt disease (24.2% vs 11.8%; p=0.065). “Any echocardiographic abnormality” was more frequent in overt than subclinical hypothyroidism (72.7% vs 52.9%; p=0.029). ECG changes were common-sinus bradycardia predominated-while lipid means (TC/LDL-C/HDL-C/TG) were comparable between groups (all p>0.60).

Conclusion: Newly diagnosed hypothyroidism demonstrates prominent electrical and diastolic functional alterations, with a higher burden of echocardiographic abnormalities in overt disease. Lipid parameters were similar at baseline across types. Routine ECG and targeted echocardiography at diagnosis, with risk-stratified management—particularly for overt hypothyroidism-are supported by these findings.

Keywords

Echocardiography; Electrocardiogram; Hypothyroidism; Lipids

Introduction

Hypothyroidism is a common endocrine disorder that contributes to dyslipidaemia, haemodynamic alterations, and broader cardio metabolic risk across populations [1]. In India, population studies estimate adult hypothyroidism prevalence around 11%, with a substantial proportion previously undiagnosed and higher burdens in inland regions [2].

Thyroid hormone deficiency adversely affects lipid metabolism-raising total cholesterol and LDL-C, often lowering HDL-C-and levothyroxine improves the lipid profile in overt disease [3]. Beyond overt hypothyroidism, subclinical hypothyroidism (SCH) has been linked in meta-analyses to modestly increased risks of coronary heart disease (especially at higher TSH), though treatment thresholds remain debated [4,5].

Guidelines generally recommend treating overt hypothyroidism and individualising therapy when TSH <10 mIU/L in SCH based on symptoms, lipids, and comorbid risk [6]. Cardiovascular manifestations span sinus bradycardia, QTc prolongation, low-voltage QRS, and T-wave changes on ECG, with improvement following euthyroidism in many cohorts [7].

Echocardiographically, hypothyroidism has been associated with diastolic dysfunction, increased wall thickness, and pericardial effusion [8]. Studies have reported pericardial effusion in 30–80% of hypothyroid patients, but modern cohorts diagnosing earlier disease show far lower rates [9].

Despite extensive global data, comprehensive Indian evidence-especially from central India-characterising ECG and echocardiographic abnormalities across overt and subclinical disease remains limited, motivating context-specific evaluation [7]. So, the current study aimed to evaluate the cardio-metabolic profile (ECG, 2D-echo, lipid parameters) in adults with hypothyroidism at a tertiary centre in central India and compare abnormalities between overt and subclinical disease.

Materials and Methods

Study Design and Setting

A hospital-based cross-sectional observational study was conducted in the Department of Endocrinology at SAIMS & PGI, Indore (Madhya Pradesh), over six months (January–June 2025).

Participants and Eligibility

Consecutive adults (≥18 years) with newly detected hypothyroidism presenting to the outpatient clinic were screened; diagnosis was biochemically confirmed using chemiluminescence immunoassay (CLIA).

Inclusion: Adults with newly diagnosed hypothyroidism consenting to participate.

Exclusion: Central hypothyroidism; prior thyroid-hormone therapy; pregnancy; chronic alcoholism; use of antiepileptics, OCPs, amiodarone, glucocorticoids, antineoplastics, or NSAIDs; co-existing hypertension/diabetes/CAD/other cardiac illness/other endocrinopathies; refusal of consent.

Operational Definitions

Overt Hypothyroidism

TSH >10 µIU/mL with low total/free T4. Subclinical hypothyroidism: TSH 4.2–10 µIU/mL with normal total/free T4.

Procedures and Measurements

Each participant underwent a structured interview and examination; 12-lead ECG (rhythm/conduction/ST-T), transthoracic 2D-echo (dimensions, wall thickness, EF, pericardial effusion), and fasting lipid profile (TC, LDL-C, HDL-C, TG) were obtained per standard protocols in NABL-accredited laboratories.

Outcomes

Primary outcomes: distribution of ECG abnormalities; prevalence and severity of diastolic/systolic dysfunction; pericardial effusion; lipid levels. Secondary outcomes: differences between overt and subclinical hypothyroidism.

Statistical Analysis

Data were entered in Excel and analysed in SPSS v26; continuous data are mean ± SD, categorical data as n (%); group comparisons used independent-samples t-test/Mann–Whitney U and χ²/Fisher’s exact test as appropriate; p<0.05 significant.

Ethical Considerations

Institutional Research Committee and IEC approval were obtained; written informed consent was secured from all participants.

Results

Table 1 shows the baseline characteristics of the study participants (N=100): age was broadly distributed with the largest share in 18–29 years (25%), followed by 30–39 (16%), 50–59 (16%), 60–69 (16%), 70–80 (15%), and 40–49 (12%); females constituted 72% and males 28%; by BMI, most participants were overweight (67%), with 21% obese and 12% normal; and by thyroid status, overt hypothyroidism accounted for 66% while subclinical hypothyroidism comprised 34%.

Table 1: Baseline Characteristics of Study Participants.

Characteristic	Category	n	%
Age group	18–29	25	25
	30–39	16	16
	40–49	12	12
	50–59	16	16
	60–69	16	16
	70–80	15	15
	Total	100	100
Gender	Female	72	72
	Male	28	28
	Total	100	100
BMI category	Overweight	67	67
	Obese	21	21
	Normal	12	12
	Total	100	100
Hypothyroidism type	Overt	66	66
	Subclinical	34	34
	Total	100	100

Table 2 shows the distribution of echocardiographic outcomes in the cohort (N=100): diastolic dysfunction was common, present in 62% overall-comprising mild (28%), moderate (24%), and severe (10%) grades-while 38% had no diastolic abnormality; systolic dysfunction was less frequent, observed in 18% with 82% showing no systolic impairment; and pericardial effusion was detected in 20% of participants, with 80% having no effusion, indicating that diastolic involvement was the predominant echocardiographic finding in this study.

Table 2: Distribution of Echocardiographic Abnormalities.

Outcome	Category	n	%
Diastolic dysfunction	None	38	38
	Mild	28	28
	Moderate	24	24
	Severe	10	10
	Total	100	100
Systolic dysfunction	No	82	82
	Yes	18	18
	Total	100	100
Pericardial effusion	Absent	80	80
	Present	20	20
	Total	100	100

Table 3 compares echocardiographic findings between overt (n=66) and subclinical (n=34) hypothyroidism and shows that diastolic dysfunction severity differed significantly between groups (p=0.007), with “none” more frequent in overt (57.6% vs 35.3%) while mild (38.2% vs 22.7%) and moderate (41.2% vs 15.2%) grades were relatively more common in subclinical disease; severe dysfunction remained uncommon in both (4.5% vs 5.9%). Systolic dysfunction did not differ significantly (15.2% in overt vs 23.5% in subclinical; p=0.155), and pericardial effusion showed a non-significant trend toward higher occurrence in overt hypothyroidism (24.2% vs 11.8%; p=0.065).

Table 3: Comparisons by Hypothyroidism Type.

Outcome	Category	Overt n	Overt %	Subclinical n	Subclinical %	p value
Diastolic dysfunction	None	38	57.6	12	35.3	0.007*
	Mild	15	22.7	13	38.2
	Moderate	10	15.2	14	41.2
	Severe	3	4.5	2	5.9
	Total	66	100	34	100
Systolic dysfunction	No	56	84.8	26	76.5	0.155
	Yes	10	15.2	8	23.5
	Total	66	100	34	100
Pericardial effusion	Absent	50	75.8	30	88.2	0.065
	Present	16	24.2	4	11.8
	Total	66	100	34	100

*Significant at 95% CI

Table 4 shows the lipid profile comparison between overt and subclinical hypothyroidism, demonstrating no statistically significant differences across parameters: mean total cholesterol was 238.27 mg/dL in overt vs 242.21 mg/dL in subclinical (p=0.612), LDL 149.27 vs 147.56 mg/dL (p=0.825), HDL 44.46 vs 45.41 mg/dL (p=0.602), and triglycerides 226.70 vs 231.38 mg/dL (p=0.651).

Table 4: Lipid Profile by Hypothyroidism Type.

Parameter	Mean (Overt)	Mean (Subclinical)	p value
Total Cholesterol (mg/dL)	238.27	242.21	0.612
LDL (mg/dL)	149.27	147.56	0.825
HDL (mg/dL)	44.46	45.41	0.602
Triglycerides (mg/dL)	226.7	231.38	0.651

Figure 1 shows the distribution of ECG findings in the cohort (N=100): sinus bradycardia was the most frequent pattern (35/100; 35%), followed by low-voltage QRS (18%) and ST–T changes (14%); RBBB (5%) and prolonged QTc (3%) were uncommon, while 25% of participants had a normal ECG. This pattern indicates a predominance of bradyarrhythmic and repolarization abnormalities at presentation, with conduction defects and QTc prolongation occurring infrequently.

Figure 1: ECG Finding Distribution (N=100).

Table 5 shows ECG patterns by hypothyroidism type: sinus bradycardia was the most frequent abnormality in both groups (overt 36.4% [24/66] vs subclinical 32.4% [11/34]), while normal ECG occurred in 27.3% (18/66) of overt and 20.6% (7/34) of subclinical cases. Low-voltage QRS was notably higher in subclinical hypothyroidism (26.5% [9/34]) compared with overt (13.6% [9/66]), whereas ST–T changes were more common in overt disease (16.7% [11/66] vs 8.8% [3/34]). RBBB was infrequent but slightly higher in subclinical (8.8% [3/34] vs 3.0% [2/66]). Prolonged QTc was rare in both groups (3.0% [2/66] overt; 2.9% [1/34] subclinical). Overall, bradyarrhythmia predominated across types, with subclinical cases showing a higher proportion of low-voltage QRS and overt cases showing more ST–T abnormalities.

Table 5: ECG Findings by Hypothyroidism Type.

ECG finding	Overt n	Overt %	Subclinical n	Subclinical %
Normal ECG	18	27.3	7	20.6
Sinus Bradycardia	24	36.4	11	32.4
Low Voltage QRS	9	13.6	9	26.5
ST–T Wave Changes	11	16.7	3	8.8
RBBB	2	3	3	8.8
Prolonged QTc	2	3	1	2.9
Total	66	100	34	100

Discussion

ECG Abnormalities

In this study, sinus bradycardia (35%) and low-voltage QRS (18%) were the dominant ECG changes alongside ST–T abnormalities, mirroring classic electrophysiological effects of thyroid hormone deficiency [7,10].

Indian and multicentre observational studies similarly report sinus bradycardia, low voltage, QTc prolongation and T-wave changes as the commonest findings in newly diagnosed primary hypothyroidism [7,11].

These alterations plausibly reflect reduced myocardial sympathovagal tone and impaired repolarisation, which tend to improve after levothyroxine therapy, underscoring the value of ECG surveillance at diagnosis and during follow-up [11].

Diastolic and Systolic Function on Echocardiography

Diastolic dysfunction affected 62% overall and differed significantly by hypothyroidism type (χ²=12.07; p=0.007), aligning with literature that documents impaired relaxation and increased LV filling pressures in hypo-thyroid states [8,12].

Prior South-Asian data and regional series describe similar patterns-diastolic dysfunction predominating over systolic impairment in untreated disease [13].

Systolic dysfunction was infrequent and not statistically different between overt and SCH in our study, echoing reports that early hypothyroidism predominantly perturbs lusitropy rather than contractility [8].

Clinically, these data argue for routine diastolic assessment in newly diagnosed hypothyroidism, even when ejection fraction appears preserved [8].

Pericardial Effusion

Pericardial effusion was more frequent in overt hypothyroidism (24.2%) than SCH (11.8%), with a non-significant trend (p=0.065), consistent with severity-linked effusion in prior studies [14].

Historically, effusions were reported in up to 30–80% of patients before contemporary screening, whereas modern series diagnosing earlier disease show markedly lower incidence as 3–6% [9,15].

Our findings likely reflect intermediate disease severity at presentation in a tertiary centre and reinforce the utility of screening echo to identify tamponade-prone effusions in symptomatic overt cases.

Lipid Profile

Mean TC, LDL-C, HDL-C and TG did not differ significantly between overt and SCH in this cross-sectional snapshot, which is compatible with reviews showing strongest lipid improvement when overt disease is treated and more variable effects in SCH [3].

Given guideline variability for SCH, integrating lipid status with symptoms and overall risk remains prudent when individualising therapy in subclinical states [6].

Overall Interpretation

Taken together, our results emphasise electrical and diastolic functional perturbations as the dominant early cardiovascular manifestations of hypothyroidism in this setting, with pericardial effusion clustering in overt disease and no clear lipid separation between groups at baseline.

These findings support routine ECG and targeted echocardiography at diagnosis, followed by risk-stratified management consistent with contemporary guidance.

Conclusion

Conclusion

In the current study of 100 adults with hypothyroidism at a central-Indian tertiary centre, ECG abnormalities (notably sinus bradycardia and low-voltage QRS) and diastolic dysfunction were common, while systolic dysfunction was uncommon and pericardial effusion trended higher in overt disease; lipid profiles were broadly similar between overt and subclinical groups-collectively supporting routine ECG and echocardiographic assessment at presentation and individualised treatment decisions, especially in SCH, in line with guideline-informed risk stratification.

Conflict of Interest

None

Sources of Funding