EFFECT OF SUBCLINICAL HYPOTHYROIDISM ON BIOCHEMICAL PARAMETERS IN PATIENTS WITH TYPE 2 DIABETES MELLITUS

Öz

OBJECTIVE: Subclinical hypothyroidism is a biochemical definition with elevated TSH (thyroid stimulating hormone) levels while free thyroid hormone levels are normal. Type 2 DM (diabetes mellitus) patients frequently have thyroid dysfunction, especially subclinical hypothyroidism and in these patients there are data suggesting that the increase in TSH levels leads to insulin resistance and dyslipidemia. In this study, we aimed to investigate the effect of subclinical hypothyroidism on biochemical parameters like serum lipid profile, fasting blood glucose levels and HbA1c levels in diabetic patients.
MATERIAL AND METHODS: This retrospective study was conducted with 99 diabetic patients. The group that thyroid function test is coherent with subclinical hypothyroidism was named as ‘patient group’ and patients with normal thyroid function test were called ‘control group’. Patients’ demographic findings, fasting blood glucose levels, HbA1c levels, total cholesterol, LDL (low density lipoprotein), HDL (high density lipoprotein) and VLDL (very low density lipoprotein) cholesterol results were obtained from electronic files. These biochemical parameters were compared between the patient and control groups.
RESULTS: The present study was conducted with a total of 99 patients, 46 (46.5%) of them are patient group and 53 (53.5%) of them are control group. Fasting blood glucose levels, HbA1c levels, total cholesterol, LDL, HDL and VLDL cholesterol, triglyceride levels were significantly higher in the patient group than the control group (p<0.05). Mean ages, free T4 levels and HDL cholesterol levels were similar between patient and control group.
CONCLUSIONS: In the literature in many studies, the coexistence of type 2 DM and thyroid dysfunction has been demonstrated. The relationship between high TSH levels and high BMI (body mass index), high blood pressure, high blood insulin levels, HOMA-IR score, high blood glucose levels, HbA1c levels, total cholesterol, LDL, HDL, VLDL cholesterol and triglyceride levels were determined. In our study, similar to the literature, fasting blood glucose, HbA1c, total cholesterol, LDL, VLDL cholesterol, triglyceride levels were found to be significantly higher in the patient group than in the control group. However, comprehensive studies are needed to accurately determine the metabolic parameters affected by thyroid dysfunction in type 2 DM patients.

Anahtar Kelimeler

• Type 2 DM
• Subclinical hypothyroidism
• Lipid profile
• Fasting blood glucose
• HbA1c

SUBKLİNİK HİPOTİROİDİNİN TİP 2 DİYABETES MELLİTUSLU HASTALARDA BİYOKİMYASAL PARAMETRELER ÜZERİNE ETKİSİ

Öz

AMAÇ: Subklinik hipotiroidi serumda serbest tiroid hormon düzeyleri normal iken; yüksek TSH (tiroid stimulan hormon) düzeylerinin saptandığı biyokimyasal bir tanımlamadır. Tip 2 DM (diyabetes mellitus) hastalarında başta subklinik hipotiroidizm olmak üzere tiroid fonksiyon bozukluklarının sıklıkla görüldüğü ve bu hastalarda TSH düzeyindeki artışın insülin direnci ile birlikte dislipidemiye yol açtığı yönünde veriler vardır. Biz de bu çalışmada; subklinik hipotiroidinin, tip 2 diyabetes mellituslu hastalarda serum lipid profili, açlık kan şekeri, HbA1c gibi biyokimyasal parametreler üzerine etkisini araştırmayı amaçladık.
GEREÇ VE YÖNTEM: Bu retrospektif çalışma tip 2 DM tanısı ile takipli toplam 99 hasta ile yapılmıştır. Bakılan tiroid fonksiyon testlerinde subklinik hipotiroidi tespit edilen diyabetik hastalar ‘hasta grubu’, tiroid fonksiyon testleri normal bulunan diyabetik hastalar ise ‘kontrol grubu’ olarak isimlendirilmiştir. Hastaların demografik özellikleri, açlık kan şekeri, HbA1c düzeyleri, total kolesterol, LDL (low density lipoprotein), HDL (high density lipoprotein) ve VLDL (very low density lipoprotein) kolesterol düzeyleri elektronik dosyalardan elde edilmiştir. Hasta ve kontrol grupları arasında biyokimyasal parametrelerin karşılaştırılması yapılmıştır.
BULGULAR: Çalışma 46 (%46,5) hasta ve 53 (%53,5) kontrol grubu olmak üzere toplam 99 hasta ile yapılmıştır. Açlık kan şekeri, HbA1c, total kolesterol, trigliserid, LDL kolesterol ve VLDL kolesterol seviyeleri hasta grubunda kontrol grubuna göre anlamlı düzeyde yüksek tespit edilmiştir (p<0,05). Hasta ve kontrol grubunun ortalama yaşları, serbest T4 düzeyleri ve HDL kolesterol seviyeleri birbirine benzer bulunmuştur.
SONUÇ: Literatürde birçok çalışmada; Tip 2 DM ve tiroid fonksiyon bozukluğu birlikteliği gösterilmiştir. Yüksek TSH düzeyleri ile yüksek VKİ (vücut kitle indeksi), yüksek kan basıncı, yüksek serum insülin düzeyi, HOMA-IR skoru, yüksek açlık kan şekeri, HbA1c düzeyleri, total kolesterol, LDL, HDL ve VLDL kolesterol, trigliserid düzeyleri ilişkisi saptanmıştır. Bizim çalışmamızda da literatüre benzer olarak açlık kan şekeri, HbA1c, total kolesterol, LDL, VLDL kolesterol, trigliserid seviyeleri hasta grubunda kontrol grubuna göre anlamlı düzeyde yüksek tespit edilmiştir. Ancak tip 2 DM ile takipli hastalarda tiroid fonksiyon bozukluğundan etkilenen metabolik parametreleri tam olarak saptayabilmek için daha geniş çalışmalara ihtiyaç vardır.

Anahtar Kelimeler

• Tip 2 DM,
• Subklinik hipotiroidi
• Lipid profili,
• Açlık kan şekeri
• HbA1c

Kaynakça

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