Diabetologia (1993) 36:57%580 Diabetologia © Springer-Verlag 1993 Letters to the editor Influence of duration of Type 1 (insulin-dependent) diabetes mellitus on 24-h ambulatory blood pressure and heart rate profile Dear Sir, The clinical value of ambulatory blood pressure monitoring has not yet been clearly established [1]. In their recent article K. W. Hansen et al. [2] report that normal circadian variation of blood pressure was moderately disturbed in a group of microalbuminuricpatients with Type 1 (insulin-dependent) diabetes mellitus. Our present study seems to indicate that duration of diabetes could have a significant influence on 24-h blood pressure profile, even in young normoalbu- minuric patients. We have examined the 24-h ambulatory blood pressure profile in 28 normotensive,well-controllednormoalbuminuric [3] diabetic pa- tients (mean _+ SD age 29.5 _+ 5.8 years) divided into two groups. Group A - 14 males with a duration of diabetes less than 5 years (mean 2.4_+ 1.9 years) and group B - 14 males with a duration of dia- betes more than 10 years (mean 12.0 _+ 5.1 years). Non-invasive24-h ambulatory blood pressure (ABP) and heart rate (HR) monitoring was performed with Spacelabs 5300 device [4]. Twenty-four hour, day and night systolic ABP were not sigNficantty different between the two groups. The 2-h systolic ABP means between 20.00 hours and 02.00 hours were, however, significantly higher in group B (Fig.l). Group B had significantly higher 24-h diastolic ABP (80+ 10 mmHg vs 71 _+7 mmHg, p < 0.01) as well as both the day (83+9 vs 74+8mmHg, p<0.05) and night (73+10 vs 62 + 8 mm Hg, p < 0.005) diastolic ABR Similarly, HR was signifi- cantly elevated in group B during the whole-day period (85 _+ 12 vs 74 + 9 min -~, p < 0.01) as well as during the day (90 + 12 vs 80 + 10 min- ~,p < 0.01) and night (74 _+ 13 vs 62 _+ 11 min- ~,p < 0.05) in com- 160 TTT!!ITi. "- -----°~ T T T T ~ 120 I a I I i i---O~.o .--- ~, ® ± i -.o___o~O~ I T T T T T ¢/J ® T T : 80 o~__?_9_._o__o .~~ ~ "I0 o y~.~ zo~z i o i i ~ ± I ± 60 ~' t ~ I l l I t I I I i 7 9 11 13 15 17 19 21 23 1 3 5 7 Time (hours) Fig.1 Twenty-four hour profile of mean systolic and diastolic blood pressure for normoalbuminuric Type I diabetic patients with a dura- tion of diabetes less than 5 years (group A, n = 14, © ) or more than 10 years (group B, n = 14, Ill). Vertical bars represent standard devia- tions. *p < 0.05, **p < 0.01, ***p < 0.001 vs group A (Student's t-test) parison to group A. The 2-11means of systolic and diastolic ABP shown in Figure 1 suggest the whole 24-h diastolic ABP profile is shifted upwards in young normoalbuminuricmales with longer du- ration of diabetes, while systolic ABP profile is disturbed only du- ring late evening and night-timein this group in comparison to short- term diabetic patients. Unfortunately, there is no general agreement concerningthe normal limits of ABP on which cliniciansshould base their decisions [1]. Recently published studies on ABP in diabetic patients [5-7] raise a question about reference ABP value, which might define elevated blood pressure and indicate the need for the- rapeutic interventionin young normoalbuminuricdiabetics, such as our patients from group B. We agree with Hansen et al. [2] that not only the mean 24-h blood pressure is important, but the normaliza- tion of the circadian blood pressure and heart rate profile should be one of the aims of the antihypertensive treatment in diabetes. Our results provide further evidence for the importance of the non-inva- sive ABP monitoringin the early detection of the blood pressure and heart rate disturbances in diabetic patients. Yours sincerely, A.Rynkiewicz, J.Furmanski, K.Narkiewicz, L.Bieniaszewski, S.Horoszek-Maziarz and chowska E. Semetkowska, B. Krupa-Wojcie- References 1. Picketing TG, O'Brien E (1991) Second international consensus meeting on twenty-four-hour ambulatory blood pressure mea- surement: consensus and conclusions. J Hypertens 9 [Suppl 8] $2-$6 2. Hansen KW, Mau Pedersen M, Marshall SM, Christiansen JS, Mogensen CE (1992) Circadian variation of blood pressure in pa- tients with diabetic nephropathy. Diabetologia 35:1074-1079 3. Mogensen CE (1987) Microalbuminuria as a predictor of clinical diabetic nephropathy. Kidney Int 31:673-689 4. Narkiewicz K, Rynkiewicz A, Furmanski J, Gan J, Kubaski A, Krupa-Wojciechowska B (1991) Relationship between fasting plasma insulin and ambulatory blood pressure in young, non- obese normotensive subjects. J Hypertens 9:505-507 5. Hornung RS, Mahler RI% Raftery EB (1988) Ambulatory blood pressure and heart rate in diabetic patients: an assessment of autonomic function. Diabetic Med 6:579-585 6. Liniger C, Favre L, Assal JPh (1991) Twenty-four hour blood pressure and heart rate profiles of diabetic patients with abnormal cardiovascular reflexes. Diabetic Med 8:420-427 7. Wiegmann TB, Herron KG, Chonko AM, MacDougall ML, Moore WV (1990) Recognition of hypertension and abnormal blood pressure burden with ambulatory blood pressure record- ings in type 1 diabetes mellitus. Diabetes 39:1556-1560 Dr. A. Rynkiewicz Second Department of Internal Diseases Akademia Medyczna, Debinki 7 PL-80-211 Gdansk Poland