CONTRACEPTION

TWO-Y R FOLLOW-UP OF C NGES IH CLINICAL CHEHI RY IN SIH POREAN NORPLA Z ROD ACCEPTORS: TABOLIC CI~NGES

Dr Kuldip Singh BS (S' pore), ED (S ' pore), ~G (Lond)

HA Population Research with Dist inct ion (Exon),

Dr 0 A C Viegas MBC~, DA, COG, MD (B'ham)

Mrs Diana L iew C 1 i nica ] B i ochemi st

B Sc

Mr Plata Singh Bi ostat i st ica I Off i cer

BSc (Hon) (Can)

Professor S S Ratn MBBS, MD, FRCS, FRCS Ed, FRCSG, FRACS,

FRCOG, FRACOG (Hon), S (Hon)

Department of Obstetrics and Gynaeco]o Natl onal Uni vers i ty of S i ngapore

National University Hospital Lower Kent Rldge Road

S i ngapore 0511

In th is longitudinal study involving 100 Singaporean acceptors, the ef fects of Norplant 2 rods on metabolic function s evalu ed. The mean serum b i ] i r u b i n during the second year remained s i gn i f i can t l y raised from i ts preinsertion value (p < 0.001). Further re the to ta l proteins and globul in were s t i l l s i gn i f i can t l y decreas (p < 0.001). Thus with respect to l i ve r function, the results s t i l I indicate poss ib le dysfunction at th~ end of two years.

As regards l i p i d metabolism, the serum t r ig lycer ides , to ta l cholesterol and LDL-chol estero] s t i ] l remain s i gni f i can t ]y decreas at the end of two years when compared to preinsertion values. The HDL-cholestero] levels which sh ed no s ign i f i can t change during the f i r s t year of use decreas s ign i f i can t l y during the second ar of use. As a resul t the

L-cho I estero I/Tota ] cho ] estero ] - HDL-cho I e stero ] creased signl f i c a n t l y and was 12. O~ ] ower than the pre- i nse~i on ra t i o (p < 0.01). S iml lar ly the LDL-cholestero]/ L-cholesterol increased during the second year of use and was 2.6~ higher than i t s preinsert ion ra t io . However, th i s increase was s t i l l not s t a t i s t l c a l ] y s ign i f i can t . As we have not incorporated a sin~u]taneous non-steroid t rea t control group, the observed changes in l i p i d metabollsm could be at t r ibuted to

Submitted for publ icat ion October 21, 1988 Accepted f o r p u b l i c a t i o n November 29, 1988

FEBRUARY 1 VOL. NO. 2 147

CONTRACEPTION

to extraneous factors such as d ie t , exercise or otller environmental changes. Nevertheless, the f indings at t heend of two.years, though speculative, s t i l l indicate Norplant®-2 use to he non-contributory to cardiovascular r isk in th is population.

The use of Norplant®-2 was not associated with any s ign i f icant ef fect on glucose tolerance a f ter two years of use.

I I

The Norplant®-2 rods system consists of two S i l as t i rods ~n which levonorgestre] has been incorporated with the pol er. Since the Norplant®-2 system consists of only two rods as compared to the six capsules in the Norplant® system, i t of fers the advantage of ease of insertion and remova]. I t would thus appear to be more eas i ly accepted by potential Norplant® acceptors. Given the long-acting nature of the Norplant®-2 rod system and the potential fo r i t s widespread use, i t ~s of part icular importance to assess i t s effects on l i p i d and other metabolic functions in acceptors from d i f fe ren t population subsets. Much of the in fo r t ion available to date has been in Caucasians from developed countries in whom disease patterns and r isk factors fo r disease d i f f e r substant ia l ly from those in developing countries. Thus,

a th is study w s designed to study ~}he effects of Norplant®-Z rod system on metabolic function in a representative South-East Asian population as part of the long-term survei ] lance of th i s r e l a t i ve l y new contraceptive i n Singapore.

The f i r s t year experience in Singapore was presented in 19 (1). In th is paper the resul ts at the end of two years are presented.

IAI_S .

One-hundred w en were recruited fo r th is study from the attendees of the F e r t i l i Control C l in ic at the National University Hospital, Singapore. These volunteers were healthy, non-smoking, non-alcohol drinkers and non--lactating women who had chosen Norplan -Z fo r contraceptive purposes. ~ Cl in ica l assessment and blood sampling for the study were done pr ior to insert ion of the imp]ants and a f te r 6, 12 and 24 months of use. The subjects were used as the i r own controls. Blood samples were obtained f r the r igh t antecubital vein at the same time of day (9 am to 11 am) on each occasion af ter an overnight fast .

Blood samples were taken for glucose (glucose oxidase meth ) (Z), to ta l protei n (Bi uret method) (3), albumin (BCG method) (4), to ta l bi I i rubin (5) , and alkal ine phosphatase (6) (modifi Bessey-Lowry Brock method) on the ASTRA-8. L-cholesterol was precipitated by magnesium phosphotungstate (7). Cholesterol (8,9) (CHOP-PAP method) and t r ig lycer ides (10) (enz}~atic hvdrolysis and determinants) were determined by k i t methods from ehri nger-Manheim. LDL-cholesterol was calculated using the method empl ed by Fri ald et at. (11) (LDL-cholestero] - Total chol esterol - ( L-cholesterol +

erides o I/1 ). 2.19

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CONTRACEPTION

Quell control In l i p i d as says were monitored by running 2 serum control pools c o ~ e r c i a l l y avai lable (normal and high levels) in every assay. For cholesterol, CV between assays at both normal (about 3 o1/1) and high (about 8 o1/1) was less than 2~ while for t r ig lycer ides , at the normal level (about 2 o i / I ) , CV was about 3% and at the higher l imi t " (about 8 o1/1) was about 5.5%. External qual i ty control was assessed by an ~nternational qua l i ty control scheme (Internat ional External Quality Assessment Sch e or IEQAS) conducted by 0 Collaborating Centre for Research and Reference Services in Cl in ical Ch i s t , Birmingham, UK.

To assess the signif icance of differences from mean values, the paired ' t ' test was used. Further comparisons were also made by observing percentage changes i n mean postinsertion Ievel s co ared to preinsert ion Ievel s which were designated as lOO~;. Where d i s t r i bu t i on of the resul ts was skewed, the Wilcoxon signed rank test of s t a t i s t i c a l signif icance using median d is t r i bu t ion was used.

RESULTS

(a) Liver Function (Table I )

The most important difference was seen in mean b i l i r u b i n levels which had increased by 66.7~ in the f i r s t 6 months of use (1). In the subsequent 6 months, there was a f a l l of a 9.3% (1). In the second year of use there was a r ther f a l l to reach a value of 0.83 mg/dl. However th is s s t i l l s ign i f i can t l y increased when compared to preinsert ion levels (p < 0.001). The s t a t i s t i c a l l y s ign i f i can t f a l l in tote] protein and globul in and the r ise in albumin seen in the f i r s t year persisted during the second year of use. The alkaline phosphatase continued to show no s ign i f i can t change a f te r 2 years of use.

(b) L i ~dMe tab (Table I I )

After 2 years of use, the tota I t r i g ] ycer i des and to ta l cholesterol were s t i l l h ighly s ign i f i can t l y low than the pre inse~ion value (p < O. OOl). However, there was no s ign i f i can t change between the values at the end of the f i r s t and second years. The LDL-cholesterol values re s t i l l s ign i f l can t ] y lower than the preinsert ion value. I t i s interest ing to note that the LDL-cho]estero] had increased by 3.2% over the second year. However, t h i s increase was not si gni f i cant. The L-cholestero] levels which showed no s ign i f i can t Changes a f te r I year of use, decreased s ign i f i can t l y during the second year of use. As a resu l t the HDL-cholesterol/Total cholesterol - L-cho]estero] ra t lo decreased s i gn i f i can t l y and was 12.0% ]ower than the pre- insert ion ra t i o (p < O.OOl). We also consider the ~L-cholesterol to HDL-cholesterol ra t io since th is is a pe inent ra t io . We found i t to have increased s ign i f i can t l y during the second year of use. The LDL-cholesterol/ L-cholesterol r io at the end of two years was thus 2. higher than pre- insert ion ra t io . HO ver, th is increase was not s t a t i s t i f l y s ign i f i can t .

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C O N T R A C E ION

LE I . BI IEMIEAL ES IN SI Z ROD ACCEPTO : LI I 7

Total Protein

n

mean ± SD ( g / d l ) i P

% d i f fe rence f r p re - i nse r t i on an

A 1 bumi n

n

mean • SD ( g / d l ) P

d i f fe rence from pre- i nse r t i on mean

99 93 8Z 7 .37 ± 0 .54 7.12. ± 0 .55 6 .95 ± 0 . 4 4

< 0 .001 < 0 .001

I00 96.6 94.5 . . . . . . . . . . . . . . . . ....... - .............. ~ - : . . . . . . . . . . . - ......... : = _ . . . . . . .............. . . . . ...... = .......................... ~ - _ . ..... . . . . . . . . . . _ _ : _

99 4 . 1 9 ± 0 .23

100

94 4 . 2 8 ± 0 .36

< 0 .05

102. !

4 .25 ± 0 . 2 4 < 0 .05

101.7

G lobu l in

n

mean +- SD (g/d1) P

% d i f fe rence from pre- inser t i on mean

A l k a l ine Phosphatase

n

mean ± ( i u / l ) P

% d i f rence f r pre- i n s e ~ i on mean

99 3 . 1 8 +_ 0 .52

100

94 2.82 ± 0.73

< 0.001

. 4

82 2 .70 ± 0 . 3 8

< 0.001

.9

99 0 .54 ± 0 .23

100

94 0 .85 ± 0 .28

< 0 . 001

157.4

82 O. ± 0 . 2 5

< 0 .001

156.6

99 64.1 ± 18.5

lO0

94 62.8 ± 19.4

NS

97 .9

82 61 .4 ± 18 .1

NS

9 6 . 4

150 F E B R U A R Y 1 VOL . 39 NO. 2

C O N T R A C E P T I O N

I I . BI IN SI Z ACCEP RS" LIPID I

Par t e r s S t u d t

Trig] erldes

n an ± SD( 1 / 1 )

P difference f r

p r e - l n s e ~ i on an

P r e - I n s e ~ i o n

99 1 .04 ± 0 . 5 8

100

After 1 y e a r o f use

94 O. ± 0 . 3 3

< 0 . 0 0 1

7 9 . 8

A f t e r 2 y e a r s o f use

8 0 0 . 8 3 ± 0 . 3 4

< 0 . 0 0 1

8 0 . 6

Cholestero]

n ¸

mean ± SD ( 171) P

d i f f e r e n c e f r o m p r e - i n s e r t i on mean

99 5 .04 ± 0 . 7 8

100

94 4 . 6 4 ± 0 . 8 1

< 0 . 0 0 1

92 .1

80 4 . 6 2 ± 0 . 7 2

< 0 . 0 0 1

9 1 . 8

L-Cho lestero I/Tota I - Choles ~l -

L-Chol estero I Rat io

n

n ± SD P

d t e rence f r

99 0 .335 ± 0 .142 0 .361 ± 0 .151

< 0 . 0 5

80 0 . 3 0 2 ± 0 .100

NS

p r e - i n s e r t t on an 100 1 0 6 . 8 . 1

~ L - C h o l e s t e r o ] / L - Chol e s t e r o I R a t t o

n 99 94 8 0 an + SD 3 .15 ± 1 .87 2 . 8 0 ± 0 .96 3 .21 ± 0 . 8 5

P NS d i f f e r e n c e f r o m ",

p r e - t n s e r t l on an 100 ) 8 9 . 2 102 .6

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CONTRACEPTION

(c) Gluco e Toleran e (Table I I I )

Oral glucose tolerance tests using 50 gm loads were performed before and af ter 1 and 2 years of Norplant®-2 use. No cl inical ly s i g n i f i c a n t changes were o b s e r v e d . D i f f e r e n c e s in t h e one hour level did reach s ta t i s t i ca l significance at the end of two years also when calculated on a paired basis, but the i r absolute l e v e l s r e m a l n ~ w i t h i n t h e normal r a n g e .

BLE I I I . 0 L GUJCOSE NCE TE C GES IN SIN PO N NORPLAN 2 ROD ACCEP RS

DIS SI

Research on contraceptives containing e~ther progestogen in general or levnorgestrel specifical ly , eg., Norplan have been shown to affe l i p i d and l i p o p r o t e i n m e t a b o l i s m ( 1 2 - 1 7 ) . I t i s t h u s n e c e s s a r y t o study the effects of Norplant®-2 rods on metabolism in d i f fe rent populations as there has been no such studies caddied out to date.

Af ter two years of Norplant®-2 use, the to ta l t r ig lycer ides and to ta l cholesterol were s t i l l s ign i f i can t ly lower than the preinsertion values although there was no s igni f icant change per se during the second year o f use. The LDL-cholesterol increased by 3.2% over the second year. However, i t is s t i l l s ign i f i can t ly lower than the preinsertion values. The L-cholesterol, which had shown no s ign i f icant changes during the f i r s t ar, decreas s ign i f i can t l y during the second year of use. As a result , the HDL-cho!esterol/Total cholesterol - L-cholesterol, which had shown a s igni f icant increase during the f i r s t year, decreased s ign i f i can t l y and was 12.0% lower than the preinsertion ra t io . The

L-cholestero']/ L-chol esterol ra t io which i s a re pert l nent ra t io was found to be s ign i f i can t l y increased during the second year of use. The LDL-chol esrerol/HDL-cho] esterol ra t io was i n fact 2.6% higher than i t s prei nsertion values. However, th i s increase was s t i ] l s ta t i st i ca] I y not s ign i f icant when compared to the prei nsertion ra t io . Thus, i t would appear that at least in Singapore women, the ~nfluence o f Norplan -2 rods on l i p i d metabolism ~re s t i l l non-contributory to cardiovascular r isk at the end of two rs. , ho ver, conclude that in the absence of non--steroid treated controls in the study, the observ~ changes could be at t r ibuted to extraneous environ ntal e f ~ c t s .

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CONTRACEPTION

Serum bl l i~Jbin levels, which had s ign i f i can t l y increased by 66.7~ in the f l r s t 6 months of use ( l ) , decreased during the second year and was 13. O~ lower than the peak value reached at 6 months. Although reassuring, the serum b l l i rub in value at the end of two years Was s t l l l s ign | f i can t Iy higher than prelnsertion values. The s t a t l s t i c a l l y s igni f icant f a l l s In to ta l protein and globulin and the r lse in albumin seen in the f i r s t year s shown to perslst during the second year of use. I t thus appears that the apparent l i ver dysfunction seen at the end of the f i r s t year .appears to be s t i l l existent at the end of the second year of use. However i t must be stressed that despite a] l these changes, the mean levels of b l l l r ub ln , tota l protein, g lobul ln and al bumln rema i ned wlthi n the normal c11 nlcal range.

The effects of Norp]ant®-2 rods on carbohydrate metabolism as ref lected by changes in the OGTT at the end of two years is minimal and no d i f f e ren t from those at the end of one year. The changes in the one hour glucose levels although s t a t i s t i c a l l y s igni f icant remain within the normal range.

LIJSION

The findings of th is study continue to emphasise the compelling need for continued close surveillance o f - t h i s re la t i ve l y new contraceptive s y s t e m . We hope to make annual a s s e s s m e n t s of a l l p a r a m e t e r s f o r t h e duration of use of the Norplan -2 rod system.

We are grateful to Family Health International and the Pooulation C o u n c i l fo r i n t r o d u c i n g Norp l an t®-2 t o S i n g a p o r e . We a r e a l s o indebted to the Department of Obstetrics and Gynaecology, National University of Singapore, for Financial support for the ent i re invest igat ion. Final ly, we would l ike to tilank Miss Prema for her secretarial assistance in preparing th is manuscript and the Norplant®-2 acceptors f o r the i r co-operation.

REF. ES

1. Singh K, Viegas O, Liew D, Singh P, Ratn SS. The Effects of Norplant®-2 Rods on Clinical Chemistry in Singaporean Acceptors after i Year of Use- Metabolic Changes. Contraception 38-441-451 ( t 9 )

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3. We i chse I baum TE- An Accurate and Rap i d thod for the Deferral t ion o f Proteins in Small Amounts of Blood Serum and P I asma ~ J Cl in Pathol 16 40-49 (1946).

4. Spencer K, Price CP. Influence of Reagent Quality and Reaction Conditi ons on the Deferral nati on of Serum Al bumi n by th~ Brom0cresol Green- Binding Method. Ann Clin B~och 14"105-115 (1977).

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5 ~ Oendrasslk L, Grof P. Simplif ied Phot e t r i c Meth s fo r the Determination of the Blood B l l l rub ln . Biochemlsche Ze i t sch r l f t 297-81-89 (1338).

m Bessey OA, Lowry OH; Brock ~J. A Method for the Rapld Dete inatlon of Alkaline Phosphatase wlth Five Cublc Mil l |metres of Serum. J B1ol Ch~ 164-321-329 (1946).

m Bursteln M, Scholnick HR, Morfin R. Rap id Method for the Isolat ion of Lipoprotelns from Human Serum by Precipitat ion with Polyanlons. J Lipid Res II.583-595 (1970).

D Stahler F, Gruber W, Stlnohoff K. Ei ne Praxi sgerechte Enz at lc Cholesterln-Besti~ung. Med Lab (Stuttg) 30-29-37 (1977).

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Trinder P. Determination of Glucose in Blood using Glucose Oxidase with an Alternative Oxygen Acceptor. Ann Clin Biochem 6-Z4-Z7 (1969).

i

Wahfield . In- Berg yer, HU (ed). Methods of Enz at ic Ana lys i s . 2nd Eng l i sh ed. Ver lag Chemle Weinheim and Academic Press, New "fork and London. 4 vols; p 1831 (1974).

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Levy RI, Fredr i ckson DS. C l i n i c Ch 18- 499-502 (1982).

Management of

lZ. Croxatto , Diaz S, Robertson DN, Pavez H. Cl in ical Chemistry in Women Treated with Levonorgestrel Implants (Norplant®) or a TCU I . Contracept ion Z7- 281-2 (1983).

13. Shaaban MM, E1wan SI, Abdallah SA, Darwish HA. Effect Su ermal Levonorgestrel Contraceptive Implants, Norplant®, Serum L i p i d s . C o n t r a c e p t i o n 30-413-419 (1984).

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14. Roberston DN. Norgestrel-Releasing S i las t i c Rods- Cl inical Effects, Biochemical Effects and In Vivo Release Rates. In: Hi shell DR, Jr , ed. Advances in Human Fer t i l i ty and Reproductive Endocrinolo , Vol 2- Long-Acting Steroid Contraception. Raven Press, New York~ pp 127-147 (1 3).

15. Shaaban , E1want SI, EI-Sharka , Farghay AS. Effect S u b d e ~ a l Levonorges t r e l C o n t r a c e p t i v e Implan ts , Norplant®, Liver Function. Contraception 30-407-412 (1984).

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16. Holma P, Robertson DN. Cholesterol and L-Cholesterol Values in n during use of Subdermal Implants Releasing Levonorgestre].

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17. Singh K, Viegas O, Liew D, Singh P. Ratnam SS. The Ef fe s o f Norplant® on C l i n i c a l Chemistry in Singaporean AcceptoPs a f t e r 1 Year of Use Metabol ic Changes. Contraception 38"79-89 (19 ).

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