Table 1.
Pre-eclampsia and risk of hypertension in later life
| Study, country | Study design | Exposure | Race | Parity | Definition of exposure | No with pre-eclampsia/No of women | Mean follow-up (years) | No with hypertension | Relative risk (95% CI) | Extent of adjustment* | |
|---|---|---|---|---|---|---|---|---|---|---|---|
| Minimum SBP, minimum DBP (mm Hg) | Minimum proteinuria g/24 h | ||||||||||
| Adams 1961,w1 UK | RC | Pre-eclampsia | White | P | —, 90 | 0.25 | 53/334† | 17.6 | 61‡ | 5.91 (3.89 to 8.98) | |
| Epstein 1964,w2 USA | RC | Pre-eclampsia | White | Any | §, § | ‡ | 48/162† | 15 | 44 | 5.34 (2.50 to 11.44) | |
| Sibai 1986,w3 USA | PC | Pre-eclampsia and eclampsia | Mixed | P | 160, 110 | 1 | 406/815 | 7.3 | 83 | 2.63 (1.66 to 4.17) | |
| Carleton 1988,w4 USA | RC | Pre-eclampsia | Mixed | P | —, 85 | 1 | 23/46 | 10.4 | 5 | 1.50 (0.28 to 8.16) | Body mass index |
| Nisell 1995,w5 Sweden | RC | Pre-eclampsia | White | Any | 140, 90 | 0.3 | 45/89 | 7 | 10 | 8.80 (1.16 to 66.59) | |
| North 1996,w6 New Zealand | RC | Pre-eclampsia | Non-white group | P | 140, 90 | 0.3 | 50/100 | 5 | 21 | 20.00 (2.79 to 143.38) | |
| Laivuori 1996,w7 Finland | RC | Pre-eclampsia | White | P | 160, 110 | 0.3 | 22/44 | 17 | 2¶ | 5.00 (0.25 to 98.52) | |
| Hannaford 1997,w8 UK | PC | Pre-eclampsia | Mixed | Any | 140, 90 | 0.3 | 2371/17 202 | 12.5** | 1299†† | 2.35 (2.08 to 2.65) | Smoking, socioeconomic status |
| Marin 2000,w9 Spain | RC and PC | Pre-eclampsia | White | P | 140, 90 | 0.3 | 80/166 | 14.2 | 42†† | 3.70 (1.72 to 7.97) | Body mass index, socioeconomic status, hypercholesterolaemia, type 2 diabetes mellitus |
| Shammas 2000,w10 Jordan | RC | Pre-eclampsia | Mixed | Any | Diagnosis of pre-eclampsia in medical records | Diagnosis of pre-eclampsia in medical records | 47/93 | 10 | 26 | 7.50 (2.42 to 23.28) | |
| Hubel 2000,w11 Iceland | RC | Eclampsia | White | Any | 140, 90 | ‡ | 30/60 | 32.65 | 12‡‡ | 5.00 (1.19 to 20.92) | |
| Sattar 2003,w12 Scotland | RC | Pre-eclampsia | White | P | 140, 90 | 0.3 | 40/80 | 19 | 9‡‡ | 3.50 (0.77 to 15.83) | Body mass index, smoking |
| Wilson 2003,w13 Scotland | RC | Pre-eclampsia and eclampsia | White | P | —, 90 | 0.3 | 443/1839 | 32 | 271§§ | 2.62 (1.77 to 3.86) | Socioeconomic status |
| Total | 3658/21 030¶¶ | 14.1 | 1885 | ||||||||
SBP=systolic blood pressure; DBP=diastolic blood pressure; RC=retrospective cohort; P=primiparous; PC=prospective cohort. All papers adjusted/matched for maternal age, parity, year of birth, and hospital of delivery.
*Women with pregnancy induced hypertension who had been classified as mild pre-eclampsia were excluded.
†List of variables used in individual studies to adjust for effect of pre-eclampsia on later risk of chronic disease.
‡Diagnosis “eclampsia,” proteinuria not recorded.
§New onset hypertension, proteinuria, and oedema in third trimester.
¶Number of cases of hypertension in control group.
**Calculated from total number of woman years.
††Codes 400-404 from international classification of diseases, ninth revision.
‡‡Hypertension defined by hypertensive prescribed.
§§Codes 401-404 from international classification of diseases, ninth revision.
¶¶21 030 women were reviewed, but 19 744 were included in meta-analysis. 296 women with pregnancy induced hypertension were excluded.