Table 1.
Study characteristics
| Article | Patient Number | Hypothyroid, No. (%) | Age, years, mean (SD) | Sex, female, No. (%) | Follow up duration, months, (range) | Definition of hypothyroidism | Interval to hypothyroidism from intervention, months | Thyroid function follow-up protocol |
|---|---|---|---|---|---|---|---|---|
| Abraham, C. R., et al. (2022) [17] | 170 | 63 (37.1) | 47.0 (14.1) | 140 (82.4) | 22.7 | TSH > 4.5 mIU/L | NR | NR |
| Ahn, D., et al. (2016) [7] | 405 | 226 (55.8) | 47.4 | 345 (85.2) | 56.4 (12-105) | TSH > 4.5 mIU/L | 4.3 | TF measured 1–3 months after surgery. If normal, follow-up thyroid function measurements were performed every 6–12 months. If subclinical hypothyroidism was identified, thyroid function measurement was performed at 3 months and repeated every 3–6 months |
| Akkari, M., et al. (2014) [18] | 14 | 3 (21.4) | NR | NR | 45 | NR | 5.6 | NR |
| Alsaleh, N., et al. (2021) [19] | 38 | 13 (34.2) | 42 (14) | 25 (65.8) | 24 | TSH > 4.8 μIU/mL | NR | TFT measured at least 6 weeks postoperatively |
| Al-Shalhoub, A. K. and S. Al-Dhahri (2017) [20] | 83 | 37 (44.6) | 38 | 67 (80.7) | 12 | TSH > 5 mIU/L | NR | The first postoperative thyroid function follow-up test was performed at different time points; whereas 40 patients (48.2%) had their first postoperative thyroid function test at 3 months, 26 patients (31.13%) had it at 6 months, 6 patients (7.2%) at 9 months, nine patients (10.8%) at 12 months and two patients (2.4%) at 18 months |
| Antunes, C. M. and A. Taveira-Gomes (2013) [21] | 109 | 40 (36.7) | 48.68 (14.93) | NR | 60 | NR | NR | NR |
| Attaallah, W., et al. (2015) [22] | 259 | 56 (21.6) | 43.1 (12.2) | 195 (75.3) | 31 (6-126) | NR | NR | NR |
| Balentine, C. J., et al. (2013) [23] | 17 | 8 (47.1) | 52.8 (16.5) | 15 (88.2) | NR | NR | NR | NR |
| Baran, J. A., et al. (2021) [24] | 110 | 31 (28.2) | 14.9 (2.5) | 94 (85.5) | 12 (1-62) | TSH > 4.5 mIU/L | 1.7 | NR |
| Barczynski, M., et al. (2010) [25] | 72 | 17 (23.6) | 40.1 (10.2) | 62 (86.1) | 60 | NR | NR | All the patients were evaluated every 3 months during the first year and every 12 months for the following years up to completion of the planned 60-month follow-up. The biochemical evaluation consisted of serum values of fT3, fT4, and TSH |
| Bauer, P. S., et al. (2013) [26] | 420 | 79 (18.8) | 50.7 | 327 (77.9) | 46.1 | NR | NR | NR |
| Beisa, V., et al. (2015) [27] | 109 | 20 (18.4) | NR | 91 (83.5) | 12 | TSH > 4 mIU/L | NR | Postoperative TSH and LT3 and LT4 tests were performed 2, 6, and 12 months after the surgery |
| Beisa, V., et al. (2011) [28] | 216 | 48 (22.2) | NR | 194 (89.8) | 20 | TSH > 4 mIU/L | NR | A postoperative TSH test was performed 2, 6 and 20 months after the surgery |
| Berglund, J., et al. (1998) [29] | 26 | 0 (0) | 48.5 | 20 (76.9) | 12 | NR | NR | Serum concentrations of thyroxine, triiodothyronine (T3) and thyroid stimulating hormone (TSH) were measured preoperatively and 1, 3, 6, 12 months postoperatively |
| Buehler, L. A., et al. (2021) [13] | 210 | 96 (45.7) | 51.1 (15.3) | NR | 50 (12-59.9) | TSH > 4.2 mIU/L | NR | NR |
| Cao, Z., et al. (2022) [30] | 378 | 110 (29.1) | NR | 280 (74.1) | NR | TSH > 4.34 μIU/ml | 3.47 | During the followup period, patients underwent thyroid function assessments at 1, 3, 6, and 12 months postoperatively, then every six months after that. However, when patients complained the clinical symptoms related to thyroid dysfunction or had suspicious TFT results, TFTs were performed at any time |
| Chen, J., et al. (2019) [31] | 43 | 11 (25.6) | 13.65 (3.04) | 34 (79.1) | 28 | TSH > 3.9 μIU/mL | 4.1 | TSH measured at least 6 weeks postoperatively |
| Cheung, P., et al. (1986) [32] | 103 | 13 (12.6) | 39 | 80 (77.7) | 36 | NR | NR | TSH and fT4 measured at 6 months, 1, 2, and 3 years postoperatively |
| Chidambaranathan, N., et al. (2021) [33]) | 128 | 26 (20.3) | 36.5 | 103 (80.5) | 27.5 (0-96) | NR | 6.5 | The first TFT was done on most occasions at around 3–6 months, and subsequently thereafter, it was repeated every 6–12 months |
| Cho, J. S., et al. (2011) [34] | 123 | 26 (21.2) | NR | 87 (70.7) | 35.7 (06-80) | TSH > 6 mIU/L | NR | Patients were followed up at 3 to 6 months intervals during the first two postoperative years, and annually thereafter |
| Cho, M. J., et al. (2021) [35] | 29 | 6 (20.7) | 40 (2) | 23 (79.3) | 12 | TSH > 4.1 μIU/ml | NR | TSH was measured before surgery, and 3 months and 1 year after surgery |
| Chong, S. S., et al. (2019) [36] | 101 | 23 (22.8) | 48 | 83 (82.2) | 29.3 | TSH > 4.2 μIU/mL | NR | TSH, total T4, T3 were measured 2 months after surgery |
| Chotigavanich, C., et al. (2016) [37] | 100 | 27 (27) | 43.6 (12.2) | 93 (93) | NR | TSH > 4 μIU/mL | NR | TFT was performed six weeks after surgery |
| Chu, K. K. W. and B. H. H. Lang (2012) [38] | 263 | 38 (14.5) | NR | 204 (77.6) | 21 (3– 62) | TSH > 5.5 mIU/L | 3 | Postoperative serum TSH was monitored regularly at 2 weeks, 3 months, 6 months, and yearly after surgery until the patient was lost to follow-up evaluation |
| De Carlucci Jr, D., et al. (2008) [39] | 186 | 61 (32.8) | 45 (14) | 163 (87.6) | 29 (6-108) | TSH > 5.5 mIU/L | NR | TSH and fT4 measured postoperatively, 4 to 8 weeks after surgery |
| Dou, Y., et al. (2020) [8] | 190 | 77 (40.5) | 40.4 (10.4) | 140 (73.7) | 36 (20-36) | TSH > 5.92 mIU/L | NR | TFT in the first month, every three months during the first postoperative year, and then every six months during the second and third years |
| Ergul, Z., et al. (2014) [40] | 50 | 8 (16) | 42.3 (12.7) | 36 (72) | 25.2 (10-43) | TSH > 4.5 μIU/mL | NR | Follow-up with thyroid function tests on the first month and then once every three months, as well as ultrasonography controls once a year were performed postoperatively |
| Ha, T. K., et al. (2019) [41] | 175 | 87 (49.7) | 45.2 (12.2) | 148 (84.6) | 7.5 (1-12) | NR | NR | TFTs were performed routinely at 1, 3, 6, and 12 months after lobectomy |
| Ito, M., et al. (2015) [42] | 150 | 56 (37.3) | NR | 116 (77.3) | 18 | TSH > 5 mIU/L | NR | Thyroid function tests were performed 1 month after surgery and every 3–6 months thereafter |
| Johner, A., et al. (2011) [12] | 117 | 25 (21.4) | 49.6 | 98 (83.8) | NR | TSH > 5.5 mIU/L | NR | TSH at 6 weeks or 3 months, and 6 and 12 months postoperatively. Followed 6 monthly or annually depending on category of TSH level |
| Kim, C. J., et al. (2020) [14] | 252 | 98 (38.9) | NR | 47 (18.7) | 38.3 (3-104) | TSH > 4.05 mIU/L | NR | TSH and fT4 levels were checked postoperatively at 1 week, 1-3 months, 6 months, and annually and/or biannually thereafter |
| Kim, S. Y., et al. (2020) [43] | 256 | 169 (66) | 43.79 (10.92) | 204 (79.7) | 64.5 | TSH > 4.7 mIU/L | NR | TFT at the time of outpatient visit every 6 months for the 1st year, with an annual follow-up thereafter |
| Koh, Y. W., et al. (2008) [44] | 136 | 58 (42.7) | 42.7 (11.7) | 115 (84.6) | 22.2 | TSH > 4 mIU/L | NR | TSH and T4 at 1, 6 and 12 months |
| Kristensen, T. T., et al. (2014) [45] | 28 | 8 (28.6) | 49 | 22 (78.6) | 12 | NR | 3.9 | TSH and thyroid hormones at 1, 3, 6 and 12 months |
| Lang, B. H., et al. (2017) [46] | 150 | 44 (29.3) | NR | 125 (83.3) | 53.5 | TSH > 4.78 mIU/L | 3.2 | Postoperative TSH and FT4 were checked at 1, 3, 6, and 12 months, then every 6 months thereafter |
| Lankarani, M., et al. (2008) [47] | 45 | 8 (17.8) | NR | NR | 12 | NR | NR | During the first three months after surgery, all patients were visited monthly, then 2 monthly and then on a 3 monthly basis. In each visit TFT of each patient was repeated and registered |
| Latoo, M. A., et al. (2020) [48] | 50 | 18 (36) | 35.58 (10.226) | 38 (76) | 12 | TSH > 4.5 mIU/L | 3.9 | The first TFT measured 1 month after surgery. If normal, follow-up measurements of thyroid function were performed at 6 months and 12 months. If subclinical hypothyroidism was identified at any time during the follow-up period, thyroid function measurement was performed 3 months after that point and was repeated every 3 months |
| Lee, D. Y., et al. (2015) [49] | 276 | 65 (23.6) | 49 | 196 (71) | 28.8 (3.67-105) | NR | 3.2 | TSH levels at 1 week, 1 month, 4 months, 1 year, and 2 years |
| Lee, S. J., et al. (2021) [50] | 353 | 193 (54.7) | 46.4 (12.3) | 258 (73.1) | 31.4 | TSH > 4.2 μIU/ml | 5.5 | TSH and fT4 levels were measured at 1 week, 1 month, and 3, 6, and 12 months, and after that at 6–12-month intervals |
| Lindblom, P., et al. (2001) [51] | 37 | 8 (21.6) | 44 | 33 (89.2) | NR | NR | NR | NR |
| McHenry, C. R. and S. J. Slusarczyk (2000) [52] | 71 | 25 (35.2) | NR | 59 (83.1) | 22 (1-86) | TSH > 3.59 μIU/mL | NR | NR |
| Meyer, C. D., et al. (2020) [53] | 369 | 111 (30.1) | 43.8 (12.3) | 278 (75.3) | 74.8 (0.43-160) | NR | NR | NR |
| Miller, F. R., et al. (2006) [54] | 90 | 24 (26.7) | 45 | 73 (81.1) | 12.4 (3-24) | TSH > 6.0 mIU/L | 6.6 | TSH test at least 8 to 10 weeks after surgery and every 3 to 4 months subsequently |
| Moon, H. G., et al. (2008) [55] | 101 | 37 (36.6) | 47.5 (12.7) | 76 (75.3) | 12 | NR | NR | TFT at 2 months and every 2 to 3 months during the follow-up period |
| Morris, L., et al. (2013) [56] | 98 | 45 (45.9) | 52.5 (13.18) | 74 (75.5) | 11.6 (1.2-51.3) | NR | 7.86 | TSH measured 4 to 8 weeks following thyroid lobectomy and then every 6 months during routine follow-up visits |
| Ng, P., et al. (2019) [15] | 901 | 123 (13.7) | 45.99 (13.24) | 682 (75.7) | 65 (3-180) | TSH > 4.5 μIU/mL | 21 | TSH measured at 6-8 weeks after thyroid surgery, and subsequently at 6 months, 1 year, 2 years, and 5 years or at latest clinic visit |
| Noureldine, S. I., et al. (2013) [5] | 105 | 10 (9.5) | 48.4 (11.7) | 99 (94.3) | 8 | TSH > 3.74 μIU/mL | NR | TFT at 4 to 6 weeks |
| Park, S., et al. (2017) [6] | 335 | 215 (64.2) | 47.9 (10.5) | 266 (79.4) | 56.2 | TSH > 4.5 mIU/L | 3.98 | TSH and fT4 measured at 2 to 3 months after lobectomy. Euthyroid patients were monitored every 6 to 12 months thereafter. Once hypothyroidism was diagnosed, all patients were regularly followed up with assessment of thyroid function every 3 to 6 months |
| Phitayakorn, R., et al. (2009) [57] | 260 | 70 (26.9) | 48 (15) | 217 (83.5) | 12 (1-172) | NR | NR | Followed with annual serum TSH level |
| Piper, H. G., et al. (2005) [58] | 66 | 12 (18.2) | 46.5 | 46 (69.7) | NR | TSH > 5.5 μIU/mL | NR | Variable. 70% of patients had an initial TSH drawn within the first 3 months, 12% within 4 to 6 months, 12% within 7 to 12 months, and 6% of patients did not have a TSH drawn within the first year |
| Rathi A., S. D., Prasad B. (2017) [59] | 60 | 19 (31.7) | NR | 56 (93.3) | 6 | NR | 2.58 | TFT at 1 month, 3 months & 6 months |
| Said, M., et al. (2013) [60] | 1240 | 417 (33.6) | 51 (14) | 1038 (83.7) | 24 | TSH > 4 μIU/mL | NR | Median time to the first TSH blood test was 5 weeks |
| Salih, A. M. (2018) [61] | 166 | 1 (0.6) | 42.68 | 139 (83.7) | 24 | NR | NR | NR |
| Sancho, J. J., et al. (2012) [62] | 47 | 14 (29.8) | 41.36 (9.6) | 46 (97.9) | 55 | NR | NR | TSH and fT4 at 3, 6, and 12 months and yearly thereafter |
| Sarkis, L. M., et al. (2017) [63] | 276 | 61 (22.1) | 51.5 (15.8) | 227 (82.3) | NR | TSH > 4.5 mIU/L | NR | TSH measured 6-8 weeks after surgery |
| Seiberling, K. A., et al. (2007) [64] | 58 | 14 (24.1) | 46.5 | 44 (75.9) | 24 | TSH > 4 mIU/L | NR | At least one TSH within 6 weeks after surgery |
| Sellami, M., et al. (2022) [65] | 214 | 66 (30.8) | 44 (14) | 197 (92.1) | NR | TSH > 5 mIU/L | NR | NR |
| Spanheimer, P. M., et al. (2011) [66] | 71 | 24 (33.8) | 50.1 | NR | 7.7 | TSH > 4.2 mIU/L | NR | TFTs at 6 weeks |
| Stoll, S. J., et al. (2009) [9] | 547 | 78 (14.3) | 50 | 440 (80.4) | 32 (12–54) | TSH > 4.82 mIU/L | NR | A TSH level was measured in all patients approximately 6 to 8 weeks after surgery during routine follow-up |
| Su, S. Y., et al. (2009) [67] | 294 | 32 (10.9) | NR | 252 (85.7) | 15 (3-150) | TSH > 4 mIU/L | 8.2 | NR |
| Tomoda, C., et al. (2011) [68] | 233 | 57 (24.5) | 51 | 193 (82.8) | 43.2 | TSH > 5.0 mIU/l and normal free T4 level lasting for more than 3 months | NR | TSH at least 4–6 weeks after surgery. Serum TSH levels were subsequently followed every 3–6 months for at least 3 years |
| Vaiman, M., et al. (2008) [69] | 1051 | 294 (28) | NR | NR | (24-360) | TSH > 6.0 mIU/L that persisted for at least 8 weeks after surgery | NR | NR |
| Wadström, C., et al. (1999) [70] | 229 | 48 (21) | 47 | 204 (89.1) | 168 (12-396) | NR | NR | NR |
| Wilson, M., et al. (2020) [71] | 100 | 47 (47) | 50.5 (16.2) | 74 (74) | 16 | NR | NR | TSH at 6 weeks, 6 months, 12 months, and then annually following thyroid lobectomy |
| Wormald, R., et al. (2008) [72] | 82 | 15 (18.3) | 53 | 71 (86.6) | 28 (18-38) | TSH > 4.5 mIU/L | 5.4 - clinical hypothyroid group 12 - subclinical hypothyroid group | TSH between 3 and 6 months and at 12 months post-operatively. Thereafter, all patients underwent thyroid function testing on an annual basis |
| Yetkin, G., et al. (2010) [73] | 104 | 24 (23) | 44.9 (11.9) | 92 (88.5) | 39.75 (5-87) | TSH > 5 mIU/L | NR | TSH and free thyroxine levels were measured in all patients at the end of the first postoperative month. If the free thyroxine and TSH concentrations were normal, the patients were followed up in 6-week intervals without thyroxine treatment |
NR Not reported, TSH Thyroid stimulating hormone, TFT Thyroid function test, fT4 free thyroxine, fT3 free triiodothyronine, T4 Thyroxine, T3 Triiodothyronine